Answer:
multiply 72 times 9
Step-by-step explanation: 648
Determine the base of right triangle by using pythagoras theorem.
![\begin{gathered} b=\sqrt[]{(15.7)^2-(8.5)^2} \\ =\sqrt[]{174.24} \\ =13.2 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20b%3D%5Csqrt%5B%5D%7B%2815.7%29%5E2-%288.5%29%5E2%7D%20%5C%5C%20%3D%5Csqrt%5B%5D%7B174.24%7D%20%5C%5C%20%3D13.2%20%5Cend%7Bgathered%7D)
Determine the area of base of figure.
Determine the volume of the figure.
So volume of the figure is 347.82 yards square.
Answer:
the question is incomplete, so I looked for a similar one:
<em>After the release of radioactive material into the atmosphere from a nuclear power plant, the hay was contaminated by iodine 131 ( half-life, 8 days). If it is all right to feed the hay to cows when 10% of the iodine 131 remains, how long did the farmers need to wait to use this hay? </em>
iodine's half life (we are given x, we need to find b):
0.5A₀ = A₀eᵇˣ
x = 8 days
we eliminate A₀ from both sides
0.5 = eᵇ⁸
ln 0.5 = ln eᵇ⁸
-0.69315 = b8
b = -0.69315 / 8 = -0.08664
since the farmers need to wait until only 10% of the iodine remains (we already calculated b, now we need to find x):
0.1A₀ = A₀eᵇˣ
0.1 = eᵇˣ
ln 0.1 = bx
where b = -0.08664
x = ln 0.1 / -0.08664 = -2.302585 / -0.08664 = 26.58 days
