If a triangle has a right angle and a 30 degree angle, what is the measure of the third angle?

60

Step-by-step explanation:

All triangles have a total measurement of 180 degrees. So to find the last angle measure subtract 90 and 30 from 180, 180-(90+30). This equals 60 degrees. Additionally, a triangle with a 90 and 30 degree angle is known as a 30-60-90 special right triangle. All of these triangles will have 60 as their third measurement.

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!