Page 160 - Math Skill - 5

158 Maths

(d) The sum of the lengths of any two sides of a triangle is always ________ than the
length of the third side.

(e) The measures of the angles corresponding to equal sides of an isosceles triangle are
________.

2. Classify the following triangles on the basis of their sides.

Q 4.2 cm P L

(a) 6.5 cm 4.2 cm (b) 6 cm 10 cm

M N
R 8 cm

X 4 cm Z J

(c) 5 cm 8 cm (d) 6 cm 6 cm

K L
Y 6 cm
3. Classify the following triangles with respect to their angles.

(a) C (b) L (c) P 62° 78° R
30° (c) 30°

A 15° 135° 40°
B M 90° 60° N Q

4. Find the third angle in each of the following.

(a) X (b) A C (c) P

35° 60° 35°

70°
30°
Y Z B Q 55° R

5. In ∆ABC, ∠A = 36°, ∠B = 73°, find ∠C.

6. One of the equal angles of an isosceles triangle is 55°. Find the other angles.

7. In a right-angled triangle, one angle measures 40°. Find the remaining angles.

8. If one angle of an isosceles triangle is 70°, find the other two angles.

9. If all the angles of a triangle are equal, find the measure of each one of them.

10. Which of the following cannot be the measures of all the three angles of a triangle?

(a) ∠A = 105°, ∠B = 30°, ∠C = 35° (b) ∠P = 72°, ∠Q = 76°, ∠R = 32°

(c) ∠X = 50°, ∠Y = 70°, ∠Z = 70° (d) ∠D = 95°, ∠E = 25°, ∠F = 60°