Area of a circle is found using the formula: A = PI x r^2 where r is the radius of the circle, which is half the diameter.
Using the information in the problem you have:
A= PI x 15^2
A = PI x 225
A = 706.5 sq. In.
Answer:
(1.5, 10.5)
Step-by-step explanation:

The origin in a graph.<span />
We can solve this problem by the rule of three.
1000 protons=10³ protons
1 proton------------------2.53*10⁻³⁷g
10³ protons---------- x
x=(10³ protons * 2.53*10⁻³⁷) / 1 proton=2.53*10⁻³⁷⁺³ protons=
=2.53*10⁻³⁴ protons
answer: 2.53*10⁻³⁴ protons