A sphere has a radius of 15 m. If the radius is divided by 5, what is the effect on the surface area? HELP PLEASE!!

Mathematics

2 answers:

Yakvenalex [24]3 years ago

8 0

i got 3 and the teacher said it was right

eduard3 years ago

8 0

Answer:

The surface area is divided by 25.

Step-by-step explanation:

The radius of a sphere is given as 15 m.

To obtain the surface area of the original sphere, substitute the radius length into the formula for the surface area of a sphere, S=4πr2.

S=4π(15)2=(4)(225)π=900π

The surface area of the original sphere is 900π m2.

To find the radius of the new sphere divide the radius of the original sphere by 5.

r=155=3

The radius of the new sphere is 3 m.

To obtain the surface area of the new sphere, substitute the radius length into the formula for the surface area of a sphere, S=4πr2.

S=4π(3)2=(4)(9)π=36π

The surface area is 36π m2.

Notice that 900π=25(36π). The surface area of the second sphere is 52=25 times less than the original surface area. The surface area of a sphere changes by the square of the factor that the radius changes.

Therefore, the surface area is divided by 25.

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