Question

each row contains the measures of 2 angles for a triangle. for each triangle, select the measure of the third angle. 30 40 50 40° and 100° 50° and 75° 60° and 90° 65° and 75°

Explanation:

Step1: Recall angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°.

Step2: Calculate the third - angle for 40° and 100°

Let the third angle be $x$. Then $x = 180-(40 + 100)=40^{\circ}$.

Step3: Calculate the third - angle for 50° and 75°

Let the third angle be $y$. Then $y=180-(50 + 75)=55^{\circ}$.

Step4: Calculate the third - angle for 60° and 90°

Let the third angle be $z$. Then $z = 180-(60 + 90)=30^{\circ}$.

Step5: Calculate the third - angle for 65° and 75°

Let the third angle be $w$. Then $w=180-(65 + 75)=40^{\circ}$.

Answer:

For 40° and 100°, the third angle is 40°.
For 50° and 75°, the third angle is 55°.
For 60° and 90°, the third angle is 30°.
For 65° and 75°, the third angle is 40°.