4b2 + 5b

I'm pretty sure $39.31 was the original sales cost because if you use proportions to find out what is 7.2% of 42.35 ( what you get you you subtract 45 by 2.65). Your equation would be x/42.35 = 7.2/100. 42.35 is the whole because tax is adding money onto your original cost, making that the part. When you cross multiply you get 100x = 304.92. Then you divide by 100 on both sides to isolate the variable, to get x = 3.04. But you don't stop there. Since 3.04 is only the 7.2%, you have to subtract that by 42. 35 to get a sum of 39. 31 as your total.

6 0

3 years ago

Please help thanks so much

Umnica [9.8K]

The formula for the volume of a sphere is the following:

$V= \dfrac{4}{3} \pi r^3$

Plug in V=5000π and solve for the radius.

$5000 \pi = \dfrac{4}{3} \pi r^3$

Divide both sides by $\pi$

$5000 = \dfrac{4}{3} r^3$

Multiply both sides by 3/4 (to eliminate the 4/3 on the right side)
Also, flip the equation so we have the unknown variable on the left side (math etiquette).

$r^3=3750$

Take the cube root of both sides

$r \approx 15.5$

Now, calculate the surface area since now we know the radius.
The formula for the surface area is the following:

$S=4 \pi r^2$

Plug in r=15.5

$S \approx 3033$

The second choice is your answer.

5 0

2 years ago

4b2 + 5b - 27