Using the Pythagorean theorem we get:

Simplifying the above result we get:

Subtracting 64 from the above equation we get:

Therefore:

Answer:
Answer: 55 miles per hour
Step-by-step explanation:
Just ignore that bot. The actual answer would be y = 1/4X - 2!
Answer:
20ln(3)
Step-by-step explanation:
Put 15 for A and solve for t.
15 = 45e^(-.05t)
15/45 = 1/3 = e^(-.05t) . . . . divide by 45
ln(1/3) = -.05t . . . . . . . . . . . take natural logs
20ln(3) = t . . . . . . . . . . . . . . multiply by 20, simplify
It will take 20·ln(3) years for the area to decrease to 15 km^2.