Question

I need helppp!! This is confusing !

Answer 1

Answer:

9

Step-by-step explanation:

So the little arrows on the lines means they are equal to each other so if you look, A to D and B to C have only one arrow meaning those two lines are the same lines

and A to B and D to C have two arrows meaning those two lines are the same

so that means if A to B is 9 and it's equal to the line D to C, then D to C is also 9

Hopefully this wasn't too confusing

Answer 2

Answer:

mCD = 9

Step-by-step explanation:

Because this polygon has opposite parallel sides, meaning each side across from each other are parallel, we know that this is a parallelogram. So:

AB ║ DC

BC ║ AD

Because this is a parallelogram, we know that, from the properties parallelograms, opposite sides of a parallelogram are congruent. This means that AB ≅ DC.

This also means that because AB = 9 and AB = DC, DC = 9.

Here's a mini two-column proof:

Statements     →     Reasons

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

mAB = 9     →     Given

AB ║ DC, BC ║ AD      →     Given

ABCD is a parallelogram      →     Definition of a Parallelogram

AB ≅ DC      →     Opposite sides of a parallelogram are congruent.

mAB = mDC      →     Definition of Congruent Segments

9 = mDC      →     Substitution Property of Equality

mCD = mDC      →     Reflexive Property of Equality

mCD = 9     →     Substitution Property of Equality