Answer
A) $$ A = \frac{3s^2}{4}\sqrt3$$
B)
$$A=3s^2$$
Work Step by Step
(A) According to the book, the area of an equilateral triangle is:
$$ A = \frac{s^2}{4}\sqrt3$$
Thus, the area of the shaded area is:
$$ A = \frac{(2s)^2}{4}\sqrt3 - \frac{s^2}{4}\sqrt3\\ A = \frac{3s^2}{4}\sqrt3$$
(B) For a square:
$$ A= s^2 \\ A = (2s)^2 -s^2 \\ A = 3s^2 $$
