Question

A triangle is placed in a semicircle with a radius of 2mm what is the area of the shaded region use the value 3.14 and do not round the number

Answer 1

1) with green checkmarks the segments, the area of which (S) I am looking for

2) S of semicircle = $S_s$

S = $S_s$ - $S\vartriangle(ABC)$

$S_s = \tfrac{1}{2}\pi*R^2 => \tfrac{1}{2}*3.14*4 mm^2 = 6.28 mm^2$

$S\vartriangle(ABC) = \tfrac{1}{2} BO*AC = \tfrac{1}{2} *2mm*4mm = 4mm^2$

$S = 6.28 - 4 = 2.28 mm^2$