The number of coins, each of radius 0.75 cm and thickness 0.2 cm to be melted to make a right circular cylinder of height 8 cm and base radius 3 cm is:460500600640

To find the number of coins needed to make a right circular cylinder, we need to calculate the volume of the cylinder and then divide it by the volume of a single coin.

1. Calculate the volume of the cylinder: The formula for the volume of a cylinder is V = πr^2h, where r is the radius and h is the height. Given that the base radius (r) is 3 cm and the height (h) is 8 cm, we can substitute these values into the formula: V = π(3^2)(8) = 72π cm^3

2. Calculate the volume of a single coin: The formula for the volume of a cylinder is V = πr^2h, where r is the radius and h is the height. Given that the radius (r) of each coin is 0.75 cm and the thickness (h) is 0.2 cm, we can substitute these values into the formula: V = π(0.75^2)(0.2) = 0.353π cm^3

3. Divide the volume of the cylinder by the volume of a single coin: Number of coins = Volume of cylinder / Volume of a single coin Number of coins = 72π / 0.353π Number of coins = 204.22

Therefore, the number of coins needed to make the right circular cylinder is approximately 204.