Answer:
y=90 degrees
Explanation:
x+y+70=180 degrees ==> these three angles make up a triangle, and the
the total sum of angles in a triangle is 180 degrees
Notice that y is on a straight line?
Straight lines are 180-degree angles called straight angles.
Hence:
(180-y)+x+70=180 ==> these three angles also make up a triangle, and the
the total sum of angles in a triangle is 180 degrees
180-y+x+70=x+y+70 ==> since both expressions equal 180, they both are
equal to each other
180-y+x+70 + y = x+y+70 + y ==> add y on both sides to isolate y to one side
180 - y + y + x + 70 = x + y + y + 70 ==> simplify
180 + x + 70 = x + 2y + 70
180+x+70 - x = x+2y+70 - x ==> subtract x on both sides to eliminate x
180 + x - x + 70 = x - x + 2y + 70 ==> simplify
180 + 70 = 2y + 70
180 + 70 - 70 = 2y + 70 - 70 ==> subtract both sides by 70 to simplify the equation
180 = 2y
y = 180/2
y = 90 degrees