If < A and < B are complementary, and < A = 3x + 4 degrees, while < B = 6x - 4 degrees, find x. Select one:
a. 10
b. 4
c. 9
d. 21

a

Step-by-step explanation:

complementary angles sum to 90° , so

3x + 4 + 6x - 4 = 90

9x = 90 ( divide both sides by 9 )

x = 10

r and t.

both are 64 degrees.

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.