Hey Guys,

I need some help trying to prove that all the angles of a rectangle are right angles.

My teacher asks us to go in depth so we have to list a ton of reasons.

So first let's have the Given

Given: Rectangle ABCD with right angle A

Reason: Given, & the it's also the definition of a rectangle.

1) Statement: Diagonal line segment AC and line segment DB

1)Reason: I constructed a diagonal line across the rectangle

2)Statement: DA || BC and AB || DC

2)Reason: Definition of parallelogram

3)Statement: AC is congruent to AC and BD is congruent to BD

3)Reason: Identity

4)Statement: (M) is for midpoint where the two diagonals meet. So

Triangle DMA is congruent to Triangle MCB

4)Reason: SSS

and here I am lost. I'm not sure if my statements and reasons are correct and in order. I will appreciate the help. Thank you, forum.