. If ABCD is a trapezium in which AB || CD and AD = BC, then:
a. ∠A = ∠B
b. ∠A > ∠B
c. ∠A < ∠B
d. None of the above
Answers
Answer:
c. is the correct answer
Step-by-step explanation:
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Question:--
If ABCD is a trapezium in which AB || CD and AD = BC, then:
a. ∠A = ∠B
b. ∠A > ∠B
c. ∠A < ∠B
d. None of the above
Answer:--
Given:
ABCD is a trapezium where AB∣∣CD and AD=BC
Construction :
Extends AB and draw a line through C point to DA intersecting AB produced at E
Prrof: AD∣∣CE (from construction) &
AE∣∣DC (AS AB∣∣CD, & AB is extended)
AECD is a parallelogram.
In AECD, both pair of opposite sides are parallel.
∴AD=CE (opposite sides of parallelogram are equal)
But AD=BC (Given)
⇒BC=CE
So, ∠CEB=∠CBE ...(1) ( In ΔBCE, angles opposite to equal sides are equal)
For AD∣∣CE,
& AE is the transversal,
∠A+∠CEB=180°
[interior angles on same side of transversal is supplementary]
∠A=180°
-∠CEB ....(2)
Also AE is line,
so, ∠B+∠CE=180°
(liner pairs)
∠B+∠CBE=180° (from (1))
∠B=180° −∠CBE ....(3) (from (2) and (3)
∠A=∠B
∴ The answer is ∠A=∠B