This is very simple. So you use two formulas:
Rectangle: Length • Width
Semicircle: Area = [tex]\frac{\pi r^2}{2}[/tex]
With that, you do 0.8 ÷ 2 = 0.4 because we will be using radius. When solved, you get 0.2512... But for this problem, I will be rounding everything to the nearest hundredths.
Area of semicircle: ≈ 0.25
Now we solve for the rectangle. That is very easy. Just multiply 0.75 • 0.8 and you get 0.6
For this problem, I'm not sure why they make you round to the nearest centimeter, but if you do, you get 1 cm. Otherwise,
Round to nearest tenth: 0.9
Round to nearest hundredths: 0.85
