Question 1:
We can tell that this shape is a parallelogram because the diagonals bisect each other, which is a property unique to parallelograms.
Question 2:
72 + 72 = 144
This is not a right angle, so this shape cannot be a square or rectangle.
Since we have congruent base angles, each of those triangles are congruent isosceles triangles.
Thus, we have 4 sides of equal length. Thus, this shape must be a rhombus.
Question 3:
We know that AB and CD (the legs) are congruent since this is an isosceles trapezoid.
8y - 18 = 7y - 4
Subtract both sides by 7y
y - 18 = -4
Add both sides by 18
y = 14
That's your answer.
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