The sum of the intersecting angles at the intersection of two parallel secant lines is 210 degrees. find these corners.

Given: straight lines AB and CD are parallel;
EP – secant;
APE angle + PED angle = 210 degrees.
Find: the degree measures of the angle APE and angle RED-?
Solution: straight lines AB and SD are parallel and angle APE and angle RED are crosswise for these straight lines and secant EP. By the property of parallel lines, the cross-lying angles formed by parallel lines are equal to each other. Then angle APE = angle PED. According to the condition of the problem, angle APE + angle ED = 210 degrees, then angle APE = angle ED = 210: 2 = 105 degrees.
Answer: 105 degrees; 105 degrees.