In geometry, you will learn that a "straight angle" is basically a straight line that has measure 180 degrees as shown below.
therefore, when you see a straight angle, you know it has measure 180 degrees and you can use that information in solving a problem, such as the one below:
find the measure of x.
hint; we are told or "given" that the measure of angle acd is 230 degrees. we see that angle acb is a straight angle and therefore know it has measure 180 degrees. therefore we can set up this equation to solve for x:
180 + 3x + 5 = 230
solve this equation and select the value of x below.
20
0
5
15