1st pic
It's a rhombus
- None of the angles are 90 degrees (can't not be rectangle or square)
- Opposite angles are equal
Top triangle
180 - ( 72 + 72 )
=180 - 144
= 36
same as bottom triangle....
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2nd pic.
Rhombus...
opposite angles are equal
so m<1 = m<2 = 160
180 - 160 = 20
m< 3 = 20/2 = 10
answer
m<2 = 160
m<3 = 10
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3rd pic.
isosceles trapezoid
The legs are congruent by definition
so AB = CD
7y - 4 = 8y - 18
7y - 8y = -18 + 4
- y = -14
y =14
answer y = 14
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pic 4
A(-5, -1), B(-9, 6) C (-1, 5) D(3,-2)
A(-5, -1) and C (-1, 5) ---find slope of 1st pair
slope = (5 + 1)/(-1 + 5) = 6/4 = 3/2
B(-9, 6) D(3,-2)---find slope of 2nd pair
slope = (-2 -6)/(3+9) = -8/12= -2/3
slope of 2nd pair (-2/3) is negative and reciprocal of the 1st pair (3/2)
so it's perpendicular