Find the surface area of a sphere with a circumference of 155 mm. Round to the nearest tenth.
Help please
c = 2pi r
so,
r = c/2pi
a = 4pi r^2 = 4pi (c/2pi)^2 = c^2/pi
a = 155^2/pi = 7647.4
Can someone answer this question with the circumference being 180?
To find the surface area of a sphere, you need to first find the radius of the sphere. The formula for the circumference of a sphere is given by:
C = 2πr
where C is the circumference and r is the radius of the sphere.
In this case, the circumference is given as 155 mm. We can rearrange the formula to solve for the radius by dividing both sides of the equation by 2π:
C/2π = r
Substituting the given circumference value, we have:
155 mm / (2π) ≈ 24.734 mm
Now that we have the radius, we can use the formula for the surface area of a sphere:
A = 4πr^2
where A is the surface area and r is the radius of the sphere.
Plugging in the value we obtained for the radius:
A = 4π(24.734 mm)^2
Calculating this expression, we get:
A ≈ 1931.78 mm^2
Finally, rounding this value to the nearest tenth, the surface area of the sphere is approximately 1931.8 mm^2.