Three angles of a quadrilateral are 81 degrees,105 degrees,and 138 degrees.Find the measure of the fourth angle.

well, they must all add up to 360, right?

so add up those three and subtract that sum from 360

To find the measure of the fourth angle in a quadrilateral, we can use the fact that the sum of the angles in any quadrilateral is always equal to 360 degrees.

So, we need to find the sum of the given three angles and then subtract it from 360 degrees to find the measure of the fourth angle.

Sum of given three angles = 81 degrees + 105 degrees + 138 degrees

Sum of given three angles = 324 degrees

Now, subtract this sum from 360 degrees to find the measure of the fourth angle:

Measure of fourth angle = 360 degrees - 324 degrees

Measure of fourth angle = 36 degrees

Therefore, the measure of the fourth angle in the quadrilateral is 36 degrees.