Answer:
1π
Step-by-step explanation:
suppose the radius of semicircle P is r,
then the radius of semicircle Q = (r+d)/2 ... d≤r
radius of semicircle R = (r-d)/2
area P = 1/2 (r)²π
area Q = 1/2 ((r+d)/2)² π = 1/8 (r² + 2rd + d²)π
area R = 1/2 ((r-d)/2)² π = 1/8 (r² - 2rd + d²)π
shaded area = P-Q-R = 1/2 r²π - 1/4 (r² + d²)π
= ((r² - d²)/4) * π
because there is no constant r value in the question and d value changes with the r change, when the vertical segment length equal the semicircle P radius (r), r=2 and d = 0
therefore the shaded area = ((2² -0²)/4)*π = 1π
Answer:
897 liters
Step-by-step explanation:
The motor oil is composed of 8 liters of natural oil and 5 liters of synthetic oil. This means there is a ratio of 8/5. We have 552 liters of natural oil to y liters of synthetic. This is the ratio 552/y. Create a proportion that compares the two ratios.
Solve by cross multiplying.
8y = 5(552)
8y = 2,760
y= 345
345 liters of synthetic oil.
Together 552+345= 897 liters of motor oil.
This is exponential decay which can be expressed as:
y=ab^t, y=final value, a=initial value, b=rate, t=time
In this case a=25000, r=(100-20)/100=0.8 so
y=25000(0.8^t), so in 4.5 years...
y=25000(0.8^4.5)
y≈$9158.93 (to nearest cent)
It should be -668 maybe answer B is a typo
