Find the number of sides of each two polygons if the total number of sides of the polygons is 13, and the sum of the number of diagonals of the polygons is 25.

Question

anonymous · Answer

Each two polygons means??

anonymous · Answer

Are there 2 polygons??

campbell_st · Answer

the number of diagonals is found using the formula 

$$d=\frac{n(n-3)}{2}$$

so you need to look at the combinations of polygons

3 + 10     have 35 diagonals in total

4 + 9       have 29 diagonals in total

just keep going until you get 25 distinct diagonals.

anonymous · Answer

8 and 5 will solve this I think..