Question

If two angles of a triangle are $60°$ each, then the triangle is

• A. Isosceles but not equilateral
• B. Scalene
• C. Equilateral
• D. Right-Angled

Answer 1

The correct option is C

Equilateral

Solve for the type of the triangle.

The sum of all three angles of an equilateral triangle is equal to $180°.$

As given in the question two angles of triangle are $60°$, let the third angle be $x$

Then, according to angle sum property of the triangle:

$60+60+x=180$

$\Rightarrow$ $120+x=180$

$\Rightarrow$ $$\begin{gathered} x=180-120 \\ =60° \end{gathered}$$

Therefore all the angles of the triangle are equal to $60°$

In geometry, an equilateral triangle is a triangle that has all its angles equal to $60°$ and all the sides are of equal length.

Hence the triangle is equilateral.