Question

Each interior angle of a regular decagon (a) 60${}^{\circ }$ (b) 120${}^{\circ }$ (c) 144 ${}^{\circ }$ (d) 180 ${}^{\circ }$

Answer 1

Each interior angles of decagon =$\frac{2n-4}{n}\times {90}^{\circ }$ = $\frac{2\times 10-4}{10}\times {90}^{\circ }=\frac{16}{10}\times {90}^{\circ }$ = ${144}^{\circ }$