Answer:
17. 1 = 2 = 45, 3 =135
18. 1 = 2 = 105.5
Explanation:
17.
isosceles trapezoid properties:
Angle 1 = Angle 2
Angle 3 = 135
sum of the angles in any quadrilateral is 360
A1 + A2 + A3 + 135 = 360
A2 + A2 + 135 + 135 = 360
2A2 = 360 - 135 - 135
2A2 = 90
A2 = 90/2 = 45
So
A1 = A2 = 45
18.
Draw straight line from edge at 1 to edge at 2
Now you have two isosceles triangle
isosceles triangle properties:
angles opposite to equal sides are equal in measure
sum of the angles in any triangle is 180
refer photo for calcukation