Can someone please help me

45°

Step-by-step explanation:

The angle with measure of 9x and the angle with measure of 3x are supplementary

9x + 3x = 180°

12x = 180 divide both sides by 12

x = 15

The angle with measure of 9x and angle a are supplementary as well

9x + a = 180

9×15 + a = 180

135 + a = 180 subtract 135 ftom both sides

a = 45°

3/4 ÷ 3/4

step-by-step explanation:

basically divide any proper fraction with itself to fit the criteria.

so if we are using 3/4, then:

3/4 ÷ 3/4 = 1

so 1 is the quotient.

and the numerators for both these fractions is 3.   and if we divide the numerators:

3 ÷ 3 = 1

we see that quotient is equal to our original quotient as well.

cosine

step-by-step explanation: