# Welcome to Planet Infinity KHMS

## 22 December, 2010

### Mathittude test- Set B

Today, in our school on the occasion of Ramanujan's Day, we conducted this test for students of classes 9 and 10.

Mathittude test -Set B

### Mathittude test- Set A

Today on the occasion of Ramanujan's Day, we conducted this test for students of classes 9 and 10 in our school.

Mathittude test

## 21 December, 2010

1. Name this geometrical shape.
2. Explore the relation between its sides.
3. Explore the relation between its diagonals. Are the two diagonals perpendicular to each other? Do they bisect each other also?
4. Draw this shape in your notebook and write the properties.

## 07 December, 2010

### Areas of parallelograms and triangles- Theorem

Theorem: Triangles having the same base and equal areas lie between the same parallels.

Given: ∆PQR and ∆SQR such that ar (∆PQR) = ar (∆SQR).

Construction: Draw PL and SM perpendicular to QR

To prove: PS//QR

(Length of perpendiculars between two parallel lines is equal)
Hence, PS// QR

## 04 December, 2010

### Recall task- Areas of parallelograms and triangles

Triangles on the same base and between same parallels are equal in area.

Parallelograms on the same base and between same parallel are equal in area.

If a traingle and a parallelogram are on the same base and between same parallels then area of triangle is half the area of parallelogram.

## 12 November, 2010

Prepare a mind map on special types of quadrilaterals and their properties.

## 11 November, 2010

### Math Quote

"A man is like a fraction whose numerator is what he is and whose denominator is what he thinks of himself. The larger the denominator the smaller the fraction."

Tolstoy, Count Lev Nikolgevich (1828-1920)

## 10 November, 2010

### Joining mid points of sides of quadrilaterals- Project

By paper folding get mid points of sides.
Form creases joining the mid points of sides in order.
Which shape is obtained?

What do you conclude?

Square
Rectangle
Parallelogram
Rhombus
Kite
Trapezium

Make a file and present your information.

## 02 November, 2010

### Video- Piano stairs "Use stairs to be healthy"

Watch this video!

## 13 October, 2010

### Finding angle

Q An angle is $14^{0}$ more than its complementary. Then the measure of the angle is

a)$38^{0}$

b) $36^{0}$

c) $76^{0}$

d) $52^{0}$

Most of students have answered a). This is not correct.

Let the angle be x, then its complement will be 90 -x.
Now, the angle is 14 degree more than the complement,
form an equaion

x = 90 - x + 14
2x = 104
x= 52

(You can orally check...52 is 14 more than (90-52 = 38))
So, the correct answer is d).

### Degree of a constant polynomial

Q The degree of a non-zero constant polynomial is

a) 1 b) -1 c) 0 d) -2

This question was there in SA1 paper for class 9.

Most of the students have selected option a). This answer is not correct.

Please note the degree of a constant polynomial is 0.

How do you write 7?

7 .$x^{0}$

So, what is its degree?

It is 0.

So, the correct choice is c).

Next time, do not commit this error.

## 10 October, 2010

### Sum of exterior angles of a polygon

What is the sum of exterior angles of a polygon?

Yes you are right!
it is 360 degrees.

## 06 October, 2010

### Activity- Talk about Math shapes

Objective: To recognise geometrical shapes and write about them.

Description of activity:
Each student is required to write his/her observations on the following shapes.

Reflective questions:
What is the complete shape?
How many different shapes are used in each shape to make it?
Write the properties of used shapes.

Make a list of Math terms used in your description.

Shape 1

Shape2
Shape 3
Shape 4

## 29 September, 2010

A plane figure having four sides is a quadrilateral.

Watch this video

## 26 September, 2010

### Ripples in water

Have you ever thrown a pebble in a pond? Have you ever noticed the formation of ripples in water? Why ripples in water always go in concentric circles and not any other geometrical shape?

This is really interesting to note that when we drop a pebble in a pond, then momentum is transferred to all molecules of water around the stone to adjust the stone. The energy is to spread equally in all directions, hence concentric circles and not squares or a triangles.

## 25 September, 2010

### Making icosahedron activity

Students of class 10D made a model of icosahedron using paper plates. All of them did the work with enthusiasm and interest.

## 01 September, 2010

### Fact sheet Circles

1. Equal chords of a circle (or of congruent circles) subtend equal angles at the center. 2. If the angles subtended by the chords of a circle (or congruent circles) at the center (or centers) are equal, then the chords are equal. 3. The perpendicular drawn from the center of the circle to a chord bisects the chord. 4. The line drawn through the center of the circle bisecting the chord is perpendicular to the chord. 5. There is one and only one circle passing through three given non-collinear points. 6. Equal chords of a circle (or of congruent circles) are eqidistant from the center (or centers). 7. Chords equidistant from the center of a circle are equal in length. 8. If two chords of a circle are equal, thten their corresponding arcs are congruent and conversly, if two arcs are congruent, then their corresponding chords are equal. 9. Congruent arcs of a circle subtened equal angles at the center. 10. The angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of the circle. 11. Angles in the same segment of a circle are equal. 12. If a line segment joining two points subtends equal angles at two other points lying on the same side of the line containing the line segment, then the four points are concylic. 13. The sum of either pair of opposite angles of a cyclic quadrilateral is 180 degrees. 14. If the sum of a pair of opposite angles of a quadrilateral is 180degrees, the quadrilateral is cyclic.

## 24 August, 2010

### Triangle Inequality

Activity
Take broom sticks of different lengths.
(Say, 4cm, 7cm and 13cm)

Can you make a triangle using these sticks?
Now, try to find a relation between the largest side and the sum of the remaining two.

Repeat this by taking few more sets of broom sticks.

What do you notice?
Based on your observations, write a conjecture about the relationship between the sum of the measures of the two sides of a triangle and the measure of the largest side of the triangle. Provide a reason for your conjecture.
Thinking questions?
Two sides of a triangle are 6 cm and 10 cm long. Determine a range of possible measures for the third side of the triangle.

Is it possible to have a triangle such that the sum of the measures of the two sides is equal to the measure of the largest side? Provide a convincing reason for your answer.

## 01 August, 2010

### Parallel lines and transversal

Watch this video

Q1 If the measure of angle 1 is 70 degrees, then find all other angles. Justify your answer.

Q2 If the measure of angle 3 is 120 degrees, then find all other angles. Justify your answer.

## 28 July, 2010

### Creative Writing Task- Lines and Angles

Use the words given in the collage and write a paragraph.

## 26 July, 2010

### Triangle with 3 sides always not possible...

Do you know why it is not always possible to draw a triangle with 3 given sides? Just watch this video...

## 05 July, 2010

### Rubric for Math activity Assessment

Rubric for Recording Math lab activity Work

Lab Ethics -(5)
(Parameters)
Brings material for activity
Takes interest in class
Regularly attend Math lab class
Takes care of property in Maths lab
Listens attentively during demonstration

Performance of Activity
(Scale 5 to 1)
Able to explain concept correctly after completion (5)
Or
Completes activity in the class independently (5)
Takes help and complete the task (4)
Works independently but not able to complete (3)
Tries to perform hands on in the lab (2)
Just initiate the task allotted (1)

File Record
(Parameters)
Index/Cover
Neatness
Submits work on time
Regularly brings file
Does correction work (if any)

## 03 July, 2010

### Video-Vertically Opposite Angles

When two lines intersect, two pairs of vertically opposite angles are formed. WATCH THIS VIDEO! (Proof : Vertically opposite angles are equal)

## 20 June, 2010

### Crossword- Basic Geometrical Terms

Across 4. lines do not intersect 7. angle with measure more than 90 degrees and less than 180 degrees 8. a "dot" on a piece of paper 9. a two-dimensional object that has no endpoints and continues 11. angle measuring 180 degrees 13. sum of two angles 180 degrees 14. triangle with all sides equal Down 1. sum of two angles 90 degrees 2. triangle with all unequal sides 3. angle with measure 90 degrees 5. angle with measure less than 90 degrees 6. points on the same line 10. triangle with two sides equal 12. two rays with common vertex

## 19 June, 2010

### Poem on Geometry by Aishwarya Hans 10G

Geometry's fun, I've heard people say,
Learn the angles in a round about way.
Lay it on the line, draw it in the air.
You can prove any shape or measure it there.

Linear thoughts put our brains in gear.
Work with triangles now becomes clear.
It's so much fun since we have the rule.
My man, Pythagoras, was really cool.

No dude can eat a piece of this Pie.
And the graphs won't grow without axis y;.
A hypotenuse is a sight to see.
Oh! I love to learn this GEOMETRY!

Aishwarya Hans

Roll no 3

Class 10-g

### Geometrical designs by Purvi Bahri 10D

Designs made by Purvi Bahri 10D

She wrote...

My designs are influenced by Glass paintings. The designs are a mixture of Geometrical shapes painted with bright and dark hues which give them an artistic feeling.
I have been able to come up with these four designs after I mixed and collaborated the ideas I got from the net and mainly from my memory of the geometric glass paintings I saw in one of
my relative's house I once visited and my mother also helped me with the paintings.