This is the area of white part / area of the entire dartboard
Therefore:
Area of the entire board
[tex]A=\pi r^2[/tex]
Where:
r = 4
[tex]A=\pi4^2=16\pi[/tex]
Area of white part is given by:
[tex]A=16\pi-2^2\pi=16\pi-4\pi=12\pi[/tex]
So, the probability is:
[tex]P=\frac{12\pi}{16\pi}=\frac{12}{16}=\frac{3}{4}[/tex]
As a percentage we have:
[tex]\frac{3}{4}\times100=0.75\times100=75\%[/tex]
Answer: 75%
