Answer:
A = 28.26 cm², P = 38 units, A = 20 units², C = 43.96 units
Step-by-step explanation:
1) Our area of a circle is πr². Since our r = 3 cm, we can just substitute for r.
A = πr²
A = (3.14)(3)²
A = (3.14)(9)
A = 28.26 cm², like in your work.
2) Our formula for perimeter is 2l + 2w. We substitute for l = 12 and w = 7.
P = 2l + 2w
P = 2(12) + 2(7)
P = 24 + 14
P = 38 units
3) The formula for a triangle's area is A = [tex]\frac{1}{2}[/tex]bh, so we substitute for b = 10 and h = 4.
A = [tex]\frac{1}{2}[/tex] bh
A = [tex]\frac{1}{2}[/tex] (10)(4)
A = [tex]\frac{1}{2}[/tex] (40)
A = 20 units²
4) Circumference is 2πr, and we substitute for r = 7.
C = 2πr
C = 2(3.14)(7)
C = (3.14)(14)
C = 43.96 units
