Given: AD ABC and AD || BC
Prove: ABCD is a parallelogram.

We don't get all the menus so we'll have to wing it.

AD ≅ BC   Given

AD || BC    Given

AC ≅ AC   Reflexive property

∠DAC ≅ ∠BCA      Alternate interior angles (of a transverse of parallel lines)

ΔDAC ≅ ΔBCA     SAS (side-angle-side)

∠DCA ≅ ∠BAC     CPCTC  (corresponding parts...)

CD || AB               Converse of alternate interior angles theorem

ABCD is a parallelogram.        Def parallelogram (AD || BC and CD || AB)

about 0.75 hours

step-by-step explanation:

the answer is b: 18

step-by-step explanation:

use the pythagorean theorem to .

a^2+b^2=c^2

plug 18 for "r"

the 2 legs are 18 and 24

18^2+24^2=c^2

324+576=c^2

900=c^2

c=30

30-12=18

18 is the radius

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