Answer
angle A = 68°
Work Step by Step
Let take angle A as α in parallelogram ABCD
therefore cos α = $\frac{length of adjacent}{length of hypotenuse}$
cos α = $\frac{10 - 7}{8}$ = $\frac{3}{8}$
therefore α = $cos^{-1}$($\frac{3}{8}$) = 68°
so angle A = 68°
