Answer:
I think they are corresponding angles
1) Add 1.2 to both sides
7k=21
2) Divide 7 on both sides.
k=3
Your answer is 3.
80 because you find the area of the triangle and subtract it from the area of the rectangle to get 80
The triangle ABC is a right angled triangle , right angled at C because it is the angle subtended by the diameter
Now OA = OB = OC = 4 cm (radii)
AB = OA + OB = 8 cm
By pythagoras theorem ,


AC =4 
shade region area = area of semicircle - area of triangle
=
- 1/2 × base × height
=1/2 × 16
- 1/2 × 4 × 
=8
- 8
=8(
)