Area blue area.

Since the radius of the circle is $7$ , the diameter is $2(7)=14$ , which is also the width of the rectangle. The length of the rectangle is $20$ . The area of the blue part is the area of the rectangle minus the area of the circle, we have

$14(20)-\pi (49) \approx$ $\color{#D61F06}\large \boxed{126}$

We can find the area of blue region by subtracting area of circle from area of triangle Here area of circle = pi r^2 = 154 Length of rectangle =20 cm and breadth = diameter of circle=2r=14cm Area of rect.=280 Area of blue region=280-154=126