Given: The penny size d is given by the equation

where n is the length of the nail.
Required: a) To solve the equation for n
b) To use the equation to find out the length of the nail with the following penny sizes: 3, 6, and 10.
Explanation: The given equation can be solved for n as follows

Now putting the value of d=3 we get

Again putting d=6 we get


Finally putting d=10 we get

Final Answer: a) The equation for n is

b) The length of the nail with penny sizes 3,6, and 10 is 5/4, 2, and 3 respectively.