# 13 year old math problem?

13 year old math question! lol,

Question:

Danny wants to build a circular fountain in his backyard. he would like to make the foutain 2.5 feet in diameter. what will the area of his foutain be?, Explain

Ok, i need the answer and HOW you got it. So i can understand the rest, Thank u!

(Note: you probaby would say: ask your parent!, Well my parents won't help.)

Update:

Omg.. this is freaking hard xD

Relevance
• 1 decade ago

There is a formula for the area of a circle.

A = π r²

π is the value pi which is approximately 3.14159

r is the radius.

Now remember that the radius is the distance from the center to the edge of the circle while the diameter is the full distance across. Thus the radius is *half* the diameter.

In your question, the diameter is 2.5 feet, so the radius is 1.25 feet.

Plug the value in to find the area.

A = π r²

A = (3.14159) * (1.25)²

A ≈ 4.9 sq. feet

P.S. Some books use 3.14 as approximate value of π and others use 22/7. You should still get about 4.9 sq. ft.

• 1 decade ago

There is a formula for the area of a circle.

A = π r²

π is the value pi which is approximately 3.14159

r is the radius.

Now remember that the radius is the distance from the center to the edge of the circle while the diameter is the full distance across. Thus the radius is *half* the diameter.

In your question, the diameter is 2.5 feet, so the radius is 1.25 feet.

Plug the value in to find the area.

A = π r²

A = (3.14159) * (1.25)²

A ≈ 4.9 sq. feet

P.S. Some books use 3.14 as approximate value of π and others use 22/7. You should still get about 4.9 sq. ft.

• 1 decade ago

this is how i would go about figuring this one out- and remember math can be fun and figured out in alot of creative ways- find the way you understand it!

But i would draw a circle (fountain)

line across circle is 2.5 feet. (diameter)

i don't remember off the top of my head for the equation for this. But its diameter times something equals area.

you got it girl...

• Anonymous

you would use the formula for area or a circle

(A = πr 2) pi times radius squared

well you divid the diameter by 2 and you get your radius = 1.25

and then you use the formula above to get the answer

• Anonymous

the area of a circle is pie(radius)^2

1. first find half of 2.5 to find the radius

2. find the square of the radius (1.25)

1.25^2= 1.5625

3. multiply 1.5625 by pie (3.1415...)

4. area will be around 4.9 square ft

• 1 decade ago

A = pid^2/4 = 6.25pi/4 = 4.9 ft^2

• Anonymous

ummm, the are of a circle is.

A = πr^2 [are of circle]

A = π(1.25)^2 [substitute 1.25 for the radius, cause radius is half of the diameter]

A = π(1.5625) [1.5625 is 1.25 squared]

A = 4.90 [answer]

i think that's what the answer is.

haha, if that's not right, someone help her.

:]

• 1 decade ago

Area of circle= pir2

pi=3.14

2=squared

A=pir2

A=3.14(1.25x 1.25)

A=3.14(1.5625)

A=4.90625

A=4.9

Source(s): My knowledge