Question

the diameter of a canadian penny is 19 millimeters. the diameter of a canadian nickel is 21 millimeters. how much greater is the area of a canadian nickel than the area of a canadian penny? show your work.

Explanation:

Step1: Find radius of penny

Radius of penny $r_1=\frac{19}{2}= 9.5$ mm.

Step2: Find area of penny

Area of penny $A_1=\pi r_1^{2}=\pi\times(9.5)^{2}=90.25\pi$ $mm^{2}$.

Step3: Find radius of nickel

Radius of nickel $r_2 = \frac{21}{2}=10.5$ mm.

Step4: Find area of nickel

Area of nickel $A_2=\pi r_2^{2}=\pi\times(10.5)^{2}=110.25\pi$ $mm^{2}$.

Step5: Find difference in areas

$A_2 - A_1=110.25\pi-90.25\pi = 20\pi\approx20\times3.14 = 62.8$ $mm^{2}$.

Answer:

$62.8$ $mm^{2}$