Answer:
Step-by-step explanation:
The equation for the area of a circle is:

. Insert 9 as your radius (r) into the equation and solve:
\pi 9^2 = 254.469
Answer:
0.6 or 
Step-by-step explanation:
Using the Pythagorean theorem (
) we get that the hypotenuse is 5.
so the cos V is adjacent over the hypotenuse. so if adjacent is 3 and hypotenuse is 5, the answer is
which equals 0.6 in decimal form.
A(t)=A0*(1/2)^(t/30)
where t=elapsed years
A0=initial mass at t=0.