Answer:
1600π mm²
7.84π m²
225π units²
81π cm²
20391.84π mm²
Step-by-step explanation:
The question is simple as soon as you understand how you solve the area.
Assuming you are talking about a circle, the area is πr², or pi * radius squared.
All you have to do is multiply each given radius by itself again and multiply that by π
π * 40² = 1600π mm²
π * 2.8² = 7.84π m²
π * 15² = 225π units²
π * 9² = 81π cm²
π * 142.8² = 20391.84π mm²
