Answer:
The area of remaining sheet is 1077cm²
Step-by-step explanation:
First, you have to find the area of circle using the formula, A = πr², where r is the radius of circle:
r = 20cm
A = π × 20²
= 400π cm²
Second, you have to find the area of rectangle:
A = 12 × 15
= 180 cm²
Lastly, you need to substact the area of rectangle feom the area of circle to find the remaining sheet that has not being cut:
A = 400π - 180
= 1077 cm² (3s.f)