Respuesta :

Answer:

a = 91

Measure of Angle A is 121 degrees.

Measure of Angle B is 107 degrees.

Measure of Angle Y is 73 degrees.

Measure of Angle C is 59 degrees.

Step-by-step explanation:

It's given that diagonal inscribed angles are supplementary, meaning they add up to 180 degrees. So to solve for a, you need to set it up like this:

a + 16 + a - 18 = 180

Add like terms:

2a - 2 = 180

Add 2 to both sides:

2a - 2 = 180

    + 2    + 2

__________

2a = 182

Divide by 2 on both sides:

a = 91

Now to get the angle measurements, all you need to do is plug in 91 for a, for example:

Angle A = a + 30

Angle A = 91 + 30

Angle A = 121

Now just do the same and plug in 91 for a, to solve for Angle B, C, and Y.