The measure of ∠JLM is 140°. The measure of ∠JKL is 75°. What is the measure of ∠KJL?

May 11, 2018

$\angle K J L$ is 65˚.

Explanation:

If $\angle J L M$ is 140˚, we can calculate $\angle J L K$. This is because the two angles are supplementary and add up to 180˚.

/_JLM + /_JLK=180˚
140˚ +/_JLK=180˚
/_JLK=180˚-140˚
/_JLK=40˚

Now, we must use the angles properties of triangles. You can learn more about them here. For this problem, we can use the fact that all the interior angles of a triangle must equal 180˚.

/_JLK+/_JKL+/_KJL=180˚

Then, we substitute in the values we know.

75˚+40˚+/_KJL=180˚
115˚+/_KJL=180˚

Because we are looking for $\angle K J L$, we need to isolate it.

/_KJL=180˚-115˚
/_KJL=65˚