Question

One angle of a triangle measures 45°. The other two angles are in a ratio of 7:20. What are the measures of those two angles?

Answer 1

35° and 100°

Explanation:

The total angle of a triangle = 180°
The total angle of two angles = 180° - 45° = 135°
One part of the ratio = 135° : (20 + 7) = 5°
The smaller angle = 5° x 7 = 35°
The bigger angle = 5° x 20 = 100°

Answer 2

35° and 100°

Explanation:

the sum of the 3 angles in a triangle is 180°

the ratio of 2 angles is 7 : 20 = 7x : 20x ( x is a multiplier )

equate the sum to the 3 angles to 180 and solve for x

45 + 7x + 20x = 180

45 + 27x = 180 ( subtract 45 from both sides )

27x = 135 ( divide both sides by 27 )

x = 5

Then

7x = 7 × 5 = 35

20x = 20 × 5 = 100

the measure of the 2 angles is 35° and 100°