Question

Use the triangle angle sum theorem to find the third angle of a triangle if the other two angles measure 25 and 68. A: 86 B: 88 C: 77 D: 87

Answer 1

The triangle angle sum theorem states that the sum of the interior angles of a triangle is always 180 degrees.

Given the two angles:
- Angle 1 = 25 degrees
- Angle 2 = 68 degrees

To find the third angle, we can set up the equation:

\[
\text{Third angle} = 180 - (\text{Angle 1} + \text{Angle 2})
\]

Substituting the values:

\[
\text{Third angle} = 180 - (25 + 68)
\]

Calculating the sum of the angles first:

\[
25 + 68 = 93
\]

Now, substituting back into the equation:

\[
\text{Third angle} = 180 - 93 = 87
\]

So, the third angle measures 87 degrees.

Thus, the correct answer is **D: 87**.