Question

Two of the angles in a triangle measure 57° and 54°. What is the measure of the third angle?

Answer 1

In a triangle, the sum of all three angles is always 180°. To find the measure of the third angle, we can use the following equation:

\[
\text{Third angle} = 180° - (\text{First angle} + \text{Second angle})
\]

Given the two angles are 57° and 54°, we can substitute these values into the equation:

\[
\text{Third angle} = 180° - (57° + 54°)
\]

Calculating the sum of the first two angles:

\[
57° + 54° = 111°
\]

Now, we can find the third angle:

\[
\text{Third angle} = 180° - 111° = 69°
\]

Thus, the measure of the third angle is \( \boxed{69°} \).