12. Two streets form an intersection. ZC and ZD are
supplementary angles. If the measure of C is 128°
and the measure of ZD is two times the value of x,
what is the value of x?
D



Answer :

To solve this question, let's follow the given information step by step:

We are given that ZC and ZD are supplementary angles, which means that the sum of angles ZC and ZD is 180° because supplementary angles add up to 180°.

1. We know the measure of angle C (ZC) is 128°.
2. We’re told that the measure of angle D (ZD) is twice the value of x, so ZD = 2x.

Since angles ZC and ZD are supplementary, their measures must add up to 180°.

So the equation based on the given information is:
[tex]\( \text{measure of angle C} + \text{measure of angle D} = 180° \)[/tex]
[tex]\( 128° + 2x = 180° \)[/tex]

Now we'll solve for x:

[tex]\( 2x = 180° - 128° \)[/tex]
[tex]\( 2x = 52° \)[/tex]

Divide both sides by 2 to solve for x:
[tex]\( x = \frac{52°}{2} \)[/tex]
[tex]\( x = 26° \)[/tex]

Therefore, the value of x is 26°.