We are asked to determine the radius of a cone given its volume and its height. To do that we will use the following formula for the volume of a cone:
Now, we solve for the radius "r". First, we multiply both sides by 3:
Now, we divide both sides by pi and the height:
Now, we take the square root to both sides:
Now, we convert the height from feet to yards using the following conversion factor:
Multiplying by the conversion factor we get that the height is 1 yd:
Now, we substitute the values:
Solving the operations:
Therefore, the radius is 21 yd.