Question

$\text{If}\Delta ABC\cong \Delta PQR\text{and it is given that}\angle A={60}^{\circ },\angle B={70}^{\circ }.\text{Then the value of}\angle R\text{is}$___ ${}^{\circ }$.

Answer 1

$\text{If}\Delta ABC\cong \Delta PQR,\angle A=\angle P={60}^{\circ }\angle B=\angle Q={70}^{\circ }\text{Now,}\angle P+\angle Q+\angle R={180}^{\circ }\text{(angles of a triangle)}\Rightarrow {60}^{\circ }+{70}^{\circ }+\angle R={180}^{\circ }\Rightarrow \angle R={50}^{\circ }$