The answer is c because all you are doing here is subbing the variable r for 5b.
We know that <span>the given side lengths are x and the height is x.
Therefore, the area of the base = </span>


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Answer:
m∠8 = 49°
Step-by-step explanation:
∠7 and ∠8 are same-side interior angles.
Remember, same-side interior angles are supplementary. This means that the sum of the angles is 180°.
Let's use the variable 'x' to represent the unknown measure of angle ∠8.

(cancels itself out)


Therefore, the measure of ∠8 is 49°.