<PRE><B>Question 761309</B>
First you must know that the total degree of an triangle,  which is 180 degree.
then we use the information given to make an equation.
Info: let x= unknown angle, x#2=20, and x#3=30
MAKING EQUATION
Since we know that the total degree of a triangle is 180, we have to add all the other 3 angles together, to get 180.
EQUATION: 20+30+x=180
solve for x
50+x=180 (added 20+30)
x=130 (180-50)
Answer: the third degree of the triangle is 130 degrees.</PRE>