Question

Two angles of a triangle are ${30}^{\circ }\text{and}{60}^{\circ }.$ What kind of triangle it is based on its angles?

Answer 1

We know,
Sum of all angles in a triangle $={180}^{\circ }$
Let the $3^{rd}\text{angle be}{x}^{\circ }$
Then,
${30}^{\circ }+{60}^{\circ }+x={180}^{\circ }$
$\Rightarrow {90}^{\circ }+x={180}^{\circ }$
$\Rightarrow x={180}^{\circ }–{90}^{\circ }$ (Subtracting both sides by ${90}^{\circ }$}
$\Rightarrow x={90}^{\circ }$
Since one angle of a triangle is 90°, it is a “Right angled triangle”