Page 183 - ICSE Math 7

EXERCISE 16.2

1. Which of the following can be the sides of a right-angled triangle?
(a) 0.5 cm, 1.2 cm and 1.3 cm (b) 2.4 cm, 3.2 cm and 7.9 cm
(c) 5.0 cm, 5.25 cm and 7.25 cm (d) 1.6 cm, 3.0 cm and 3.4 cm
2. Find the length of the unknown sides in the following right-angled triangles.

10 cm x 15 cm
(a) 8 cm (b) 15 cm (c) 24 cm x (d) x
12 cm
8 cm
x 7 cm

3. Find the unknown length in the given figure. 50 m 14 m 50 m

x
4. A 13 m long ladder when set against the wall of a house reaches a height of 12 m. How far is
the foot of the ladder from the wall?
5. Two poles 18 m and 13 m high, stand upright in a playground. If their feet are 12 m apart, find
the distance between their tops.
6. A man goes 30 km due north and then 40 km due east. How far away is he from his initial position?
7. If the square of the hypotenuse of an isosceles right-angled triangle is 242 sq. cm., find the length
of each of the other two sides of the triangle. P
8. Angles Q and R of ∆ PQR are 47° and 43°. Write which of the following is
true:
2
2
2
2
2
(a) PQ + QR = RP (b) PQ + PR = QR 2
2
2
(c) RP + QR = PQ 2 Q 47° 43° R
D
A
9. In the adjoining figure, find the length of AD. 4 cm 12 cm
B 3 cm C

AT A GLANCE

¾ A triangle has six elements, i.e., 3 sides and 3 angles.
¾ (a) Classification according to sides (b) Classification according to angles

Scalene triangle All sides different Acute-angled triangle All angles less than 90°

Isosceles triangle Two sides equal Right-angled triangle One angle equal to 90°

Equilateral triangle All sides equal Obtuse-angled One angle greater than
triangle 90°

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