How many diagonals can be drawn in a pentagon?

A pentagon has 5 sides. We obtain the diagonals by joining the vertices in pairs.
Total number of sides and diagonals,
= ⁵C₂
= $$\frac{{5 \times 4}}{{2 \times 1}}$$
= 5 × 2 = 10
This includes its 5 sides also.
⇒ Diagonals = 10 – 5 = 5
Hence, the number of diagonals
= 10 – 5
= 5