The half-life of the radioactive substance is 67.95 hours.
Answer: B. 19.9
Step-by-step explanation: Set up an equation where sin and the degree angle is in the numerator, and the side length is in the denominator.
Sin65/8 = Sinx/3
Plug Sin65 into your calculator and you will get 0.9063. Divide this number by 8.
0.9063/8 = 0.1133
Your equation is now 0.1133 = sinx/3
Multiply by 3 on each side.
0.3399 = sinx
Put sin on the left side. It will look like:
Sin^-1(0.3399) = x
Press enter on your calculator. You will get
X = 19.9.
The correct answer should be A
