Page 181 - Start Up Mathematics_7

6. A ladder reaches a window which is 12 m above the ground on one side of the street. Keeping
its foot at the same point, the ladder is turned to the other side of the street to reach a window
5 m high. Find the width of the street if the length of the ladder is 13 m.

Thinking Skills

1. An angle of a triangle is equal to the sum of the other two angles. Also, one of the angles is
one-third of the largest angle, find the angles of the triangle.

6 A
2. Show that the sum of the measures of exterior angles of a triangle
is 360°. Find whether or not the same result is valid for any convex 2
polygon. 5
B 1 3
4 C

3. Find the value of the unknown angles x and y marked 35° x 85°
in the given figure.

y

Q

4. In the given figure, SP || RQ. Find the measure P T
of the length of PQ. 12 cm
4 cm

S 6 cm R

5. Look at this grid paper. Assuming each square to be of dimension 1 cm × 1 cm, calculate the
length of PQ and RS.

Q

S

P R

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