Answer:
x=-20
Step-by-step explanation:
Step-by-step explanation:
Very quick and effortless example of vertical angles in the attached image. When 2 straight lines intersect, the 2 angles opposite each other at that point are vertical angles, and they are always congruent.
I'd say it's the 3rd option:
"Vertical angles are a pair of non-adjacent angles formed by two intersecting lines."
but any of the first three could be technically true really. Adjacent angles are 2 angles that share a side, and vertical angles cannot share one.
Answer:
The proof is given below.
Step-by-step explanation:
Given a parallelogram ABCD. Diagonals AC and BD intersect at E. We have to prove that AE is congruent to CE and BE is congruent to DE i.e diagonals of parallelogram bisect each other.
In ΔACD and ΔBEC
AD=BC (∵Opposite sides of parallelogram are equal)
∠DAC=∠BCE (∵Alternate angles)
∠ADC=∠CBE (∵Alternate angles)
By ASA rule, ΔACD≅ΔBEC
By CPCT(Corresponding Parts of Congruent triangles)
AE=EC and DE=EB
Hence, AE is conruent to CE and BE is congruent to DE