Question

Angles a and b are complementary angles. If m A = (3x + 9)° and m

ZB = (x - 11)°, then find the measure of angle a

Answer 1

78°

Explanation:

Since, angles A and B are complementary.

`\therefore m\angle A + m\angle B = 90\degree \\</p><p>\therefore (3x+9)\degree + (x - 11)\degree = 90\degree \\</p><p>\therefore (3x +x +9-11)\degree = 90\degree \\</p><p>\therefore (4x - 2)\degree = 90\degree \\</p><p>\therefore 4x - 2 = 90\\</p><p>4x = 90+2\\</p><p>4x = 92\\ \\ x = (92)/(4) \\ \\ x = 23 \\ \\ \because m\angle A = (3x+9)\degree \\ \therefore \: m\angle A = (3 * 23+9)\degree \\ \therefore \: m\angle A = (69+9)\degree \\ \huge \red{ \boxed{ \therefore \: m\angle A = 78\degree }}`