thank you!
2006-08-21 16:37:46 · 25 answers · asked by cer 2 in Science & Mathematics ➔ Mathematics
how about the radius is 8, now solve explaing the solution.
2006-08-21 16:52:33 · update #1
Area equals pi times the SQUARE of the radius.
2006-08-21 16:41:36 · answer #1 · answered by The Nerd 4 · 2⤊ 0⤋
First: you don't need both the radius and the diameter. In fact, the two are totally dependent: the diameter is simply twice the radius. If you have the radius, multiply by two to get the diameter. If you have the diameter, divide by two to get the radius.
Now, it turns out that for ever circle in the entire world, no matter how big or how small, the area of a circle is given by a simple formula: take its radius, multiply it by itself, and then multiply that number by pi. "Pi" is simply another way of saying the number 3.14 (it's actually goes on a little ways past the decimal place--forever, actually!, but you just need to remember 3.14 for the vast majority of calculations).
Another way of saying this is: to find the area of a circle C.
(1) Get the radius of C. Call the radius r.
(2) Compute r^2. That's "r squared", or r times r.
(3) Multiply step (2) by pi.
Let's take a circle of diameter 20 feet. We know that it's radius is simply half the diameter, or 10 feet. We square its radius and get 100 square feet. Then we multiply 100 by pi, and get 314 square feet. So a circle that's 100 feet in diameter has a area of 314 square feet.
2006-08-21 16:59:11 · answer #2 · answered by cutetom26 1 · 0⤊ 0⤋
If the radius is 8 then the diameter has to be 16 because the formula of the diameter is two times the radius.
If the diameter is 4, then the radius is 2.
2006-08-22 02:54:28 · answer #3 · answered by Yonamaria 2 · 0⤊ 0⤋
Stunning, out of 7 answers 4 are wrong...
AREA is measured in square units. The AREA of a circle is Pi (3.1415926...) times the SQUARE of the radius. In other words, A = Pi * r * r.
CIRCUMFERENCE is measured in linear units. The Circumference of a circle is two times Pi times the radius. In other words, C = 2 * Pi * r.
2006-08-21 16:52:12 · answer #4 · answered by Mustela Frenata 5 · 0⤊ 0⤋
radius=distance frm centre of circle 2 th circumference
diameter=2(radius)
so u can c that both r interdependent.
If u know 1 u can find th area easily.
diameter(d)=2(radius)(r)
or similarly, r=d/2
now for area,
area of circle(A)=(pi)r^2
value of pie can b taken 22/7 or 3.14
In ur case radius=8
so,area=(pi)8^2
=22/7*64
=201.14cm^2(till 2 places of decimal)
answers may b different if u calculate using 3.14 as value of pie but both wil b rght.
b vry particular bout unit,if radius is in cm area wil b cm^2
2006-08-21 17:45:13 · answer #5 · answered by katie 1 · 0⤊ 0⤋
Area=pi*r^2
Area=pi*(d^2/4)
2006-08-21 16:41:57 · answer #6 · answered by raj 7 · 1⤊ 0⤋
PI R Squared
3.1415926*Radius*Radius
3.1415926 is PI on a calculator
2006-08-21 16:45:26 · answer #7 · answered by doug1kid 2 · 0⤊ 0⤋
Area = 2 x pi x radius } to the second power.
2006-08-21 16:42:32 · answer #8 · answered by themarkster 1 · 0⤊ 2⤋
A = Pi*r^2
Circumferance - 2*pi*r
Diameter= 2*r
Plug and chug.
2006-08-21 16:44:02 · answer #9 · answered by Cabana C 4 · 0⤊ 0⤋
pie times radius squared
2006-08-21 16:43:23 · answer #10 · answered by pba_ams_eahb 3 · 0⤊ 0⤋