Find the area of the semi-circle shown.

(a)  

Find the perimeter of the semi-circle shown.

(a)  

Find the perimeter of the semi-circle shown.

(a)  

Find the area of this triangle.

(a)  

Find the area of this triangle.

(a)  

Find the area of this triangle.

(a)  

Find the area of the blue triangle.

(a)  

Find the unknown side of the triangle.

(a)  

Find the value of $$a$$ .

(a)