Page 282 - Start Up Mathematics_6

Section C
3. Fill in the blanks: 1 M × 5 = 5 M
(a) If two ratios are __________, then they are in proportion.

(b) If 20, 40 and x are in continued proportion, then x is equal to __________.
(c) Scalene triangle has __________ line of symmetry.
(d) The sum of measures of angles of a set square is __________.
(e) Exactly __________ circle(s) can pass through three non-collinear points.

Section D

4. Give one word or sentence for the following: 1 M × 5 = 5 M
(a) What is perpendicular bisector of a line?
(b) Write the mean proportion between 27 and 48.

(c) Draw all the lines of symmetry of an isosceles triangle.
(d) Find the ratio of 40 minutes to 1.5 hours.
(e) What do you mean by collinear points?

Section E

5. Father wants to divide ` 460 between his sons Manish and Shivam in the ratio of their ages. If Manish
is 12 years old and Shivam is 8 years old, find how much will Manish and Shivam get? 2 M

6. Draw a triangle ABC where AB is 4 cm, BC is 3 cm and CA is 5 cm and then construct all the possible
lines of symmetry. Also, write the steps of construction. 3 M

Maths Lab Activity

Given below are 3 concurrent lines intersecting at O and equally inclined to each other.
Consider a circle with centre A as shown. Find its image, a m n
circle with centre B, after it is reflected in line l. Next find
the image of the circle with centre B after reflecting it in line
m. Let it be a circle with centre C. Finally find the image of B
the circle with centre C after reflecting it in line n. Let it be O l
a circle with centre D. A
Answer the following questions:
(a) Which single line could be used to find the reflection of the original
circle to get the final image?
(b) Why such a line is possible?
(c) What other name is given to a single reflection of a circle with centre A to a circle with centre D about
the point O?
Note: You can apply paper folding technique to find and verify the image of circles.

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