WRITE A TWO-COLUMN PROOF. .
Given:
l3 || l4
l1⊥ l4
l1 || l2
Prove:
∠4 is a right angle,

Please? Thank you.

Question

WRITE A TWO-COLUMN PROOF. .
Given:
l3 || l4
l1⊥ l4
l1 || l2
Prove:
∠4 is a right angle,

Please? Thank you. <3

anonymous · Answer

This didn't by any chance come with a diagram, did it?

anonymous · Answer

Oh, right. Sorry. 
|dw:1377958672911:dw|

anonymous · Answer

Okay. Two column proofs are hard to type, so I've put the stuff that should go in the second column - the reasons - in brackets beside the corresponding statement.

Proof:

$\angle 1$ is a right angle  ( $l1 \perp l4$ )
$\angle 2$ is a right angle  ( $l3 \parallel l4$ and corresponding angles are equal )
$\angle 3$ is a right angle  ( $l1 \parallel l2$ and corresponding angles are equal )
$\angle 4$ is a right angle  ( opposite angles are equal )

anonymous · Answer

Oh, thank you. :)

anonymous · Answer

You're welcome :)