# How do you find the measure of the missing angle in the triangle 10+105+x=180^circ?

## Original wording: How do you find the measure of the missing angle in the triangle $10 + 105 + x + {180}^{\circ}$?

Jul 9, 2017

If you mean $10 + 105 + x = 180$, then $x$, the missing angle, is ${65}^{o}$.

#### Explanation:

The way the question is written is confusing since all the operators are plus signs.

PRESUMING (and this is my presumption which, if wrong, will make the answer irrelevant) that the last plus sign was meant to be an equal to sign, it means that we know two angles of the triangle to be ${10}^{o}$ and ${105}^{o}$. Since the three angles of a triangle add up to ${180}^{o}$, we can write:

$10 + 105 + x = 180$

$115 + x = 180$

Subtract $115$ from each side.

$115 - 115 + x = 180 - 115$

$x = 65$

The unknown angle, $x$, is ${65}^{o}$.