Question

Find out the difference of the squares of the number of line symmetries in a regular pentagon and a rectangle.

Answer 1

A regular pentagon has has 5 lines of symmetries whereas a rectangle has 2 lines of symmetries.

According to the question, we need to find the difference of squares of the numbers i.e. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> $5^2$ - <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> $2^2$ which is equal to 25 - 4 = 21.

Hence the required answer is 21.