This is a geometry question!
Please give reasoning with your answer!
I can and will mark a "real" answer brainliest!

ΔABD ≅ ΔCDB

Step-by-step explanation:

Since a = 3, we can sub 3 into the expressions and then get a value for each side length.

AB: 3 + 7 = 10

BC = 16

CD: 12 - 2 = 10

DA: 18 - 2 = 16

Hence:

AB = CD (both have sidelengths of 10)

AD = CB (both have sidelengths of 16)

BD = BD (common line)

Therefore: ΔABD ≅ ΔCDB      Q.E.D.

step-by-step explanation:

there is a formula i can give you:

it is r^2*n*sin(360/n) divided by 2 where r represents the "radius" and n is the number of sides.

plug them in:

(10sqrt(3))^2*6*sin(360/6) divided by 2

100*3*6*sin(60) divided by 2

900*sin(60)

900*sqrt(3)/2

450*sqrt(3)

approx is 779.4 cm^2

linear pair postulates