an iron bar measures 11 cm x 7 cm x 5 cm it is melted down to make a cylinder height of 9 cm what is its radius
11 x 7 x 5 cm^3 = pi*R^2*9
Solve for R
R = sqrt[385/(9*pi)] cm
You do the numbers
To find the radius of the cylinder, we need to consider that the volume of the iron bar before being melted is equal to the volume of the cylinder it is turned into.
Let's calculate the volume of the iron bar:
Volume = Length x Width x Height
Volume = 11 cm x 7 cm x 5 cm
Volume = 385 cm³
Since the volume of the iron bar is equal to the volume of the cylinder, we can use the formula to find the volume of a cylinder:
Volume = π x radius² x height
Now, let's substitute the known values into the formula:
385 cm³ = π x radius² x 9 cm
To solve for the radius, we need to rearrange the equation:
radius² = 385 cm³ / (π x 9 cm)
radius² = 13.518 cm³
radius ≈ √(13.518)
radius ≈ 3.684 cm
Therefore, the radius of the cylinder is approximately 3.684 cm.