Every triangle has an angle measure of 180 degrees.
so 42+20+x (where x is the measure of the third angle)=180
Combine like terms.
62+x=180
Subtract 62 from both sides
x=118.
Square root of three- 1.73205
Square root of five- 2.23607
She has to 40 more laps. 50% is a half, so 40 is half of something. so you are dividing 40 by a half, which is 80. half of 80 is 40.
