Question

8. PRST is a trapezoid with PR || TS. If m∠P = 40º what is m∠T?

Answer 1

∠

Trapezoid PRST

Lines PR and TS are parallel crossed by a perpendicular line PT.

If you link both paralel lines with an F shaped line, you'll get that ∠P and the external angle ∠T' are corresponding angles, this means that they are congruent.

Now these angles are a linear pair, this means that they share a vertex (T) and a line (TS) and both add up to 180º (i.e. they are supplementary), so that

∠T+∠T'=180º

From this expression you can calculate the value of the inner angle ∠T