The volume of a cylinder is 189 cm. The height of the cylinder is 21 cm. What is the radius of the cylinder?
The formula for the volume of a cylinder is V = πr^2h, where V is the volume, r is the radius, and h is the height.
Given that the volume (V) is 189 cm^3 and the height (h) is 21 cm, we can substitute these values into the formula to get:
189 = πr^2 * 21.
To find the radius (r), we need to isolate the variable. First, we can divide both sides of the equation by 21:
189/21 = πr^2.
Simplifying the left side gives:
9 = πr^2.
To solve for r, we can divide both sides by π. Using an approximate value of π ≈ 3.14, we have:
9/π ≈ r^2.
Approximating the value of 9/π gives:
2.86 ≈ r^2.
To find r, we can take the square root of both sides:
√(2.86) ≈ √(r^2).
Approximating the square root of 2.86 gives:
1.69 ≈ r.
Therefore, the radius of the cylinder is approximately 1.69 cm.