Answer:
A. 19.5
Step-by-step explanation:
Diagonals of a rhombus intersect at right angles. Therefore the angle opposite to AD = 90°.
Thus:
90° + x + 3x + 12 = 180° (sum of ∆)
Add like terms
102 + 4x = 180
Subtract 102 from each side
4x = 180 - 102
4x = 78
Subdue both sides by 4
x = 19.5
x=3/2-1/4
8x+2y=12
move the variable to the right side and change the sign.
8x=12-2y
divide both sides of the equation by 8
x=3/2-1/4y
the final solution is
Answer: 4
