Question

19. Find the volume of a sphere with radius 9.25 cm. Use 3.14 as an approximation for pi. Round the answer to two decimal places.
A. 3313.55 cm3
B. 358.4 cm3
C. 1864.82 cm3
D. 114.08 cm3





20. Evaluate: -16 minus w, when w = -23.
A. 7
B. -39
C. -7
D. 39




25. If ∠A and ∠B are complementary angles, and ∠A = 27°, find ∠B.
A. 63°
B. 65°
C. 70°
D. 73°





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The numbers
In the front



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Answer 1

19. The formula for finding the volume of a sphere is 4/3πr^3
The problem says the radius is 9.25 cm.
Just plug in the numbers and solve:
4/3(3.14)(9.25^3)
9.25^3 = ~791.45
4/3(3.14)(791.45)
4/3 • 3.14 = ~4.19
4.19 • 791.45 = 3316.1755
It says to round to 2 decimal places so the answer to this question would be 3316.18.
That means 3316.18 is the volume of the sphere.

20. It's always best to change words into an equation.
-16 - w
w = -23
Plug in the number to the variable:
-16 - (-23)
Double negatives (a negative being subtracted) turn into a plus (positive being added).
-16 + 23 = 7
So the answer is 7.

25. Complementary angles are angles with a sum of 90º.
If angle A is 27º, just subtract that from 90º to get the measure of angle B.
90 - 27 = 63
So angle B is 63º, and the answer is A.