Q4 of 45 Page 27

The measure of one of the angles of a triangle is twice the measure of its smallest angle and the measure of the other is thrice the measure of the smallest angle. Find the measures of the three angles.

Let the measure of the smallest angle be x


Measure of second angle = 2x


Measure of third angle = 3x


In a triangle we know sum of interior angles is 180°


∴ x + 2x + 3x = 180°


⇒ 6x = 180°


⇒ x = 180°/6


⇒ x = 30°


Measure of smallest angle = x = 30°


Measure of second angle = 2x = 2 × 30° = 60°


Measure of third angle = 3x = 3 × 30° = 90°


More from this chapter

All 45 →
2

In ΔPQR, ∠P = 70° ∠Q = 65° then find ∠R.

 3

The measures of angles of a triangle are x°, (x – 20)°, (x – 40)°. Find the measure of each angle.

 5

In figure 3.9, measures of some angles are given. Using the measures find the values of x, y, z.

 6

In figure 3.10, line AB || line DE. Find the measures of ∠DRE and ∠ARE using given measures of some angles.