Find the balance in the account.

$2,100 principal earning 4%, compounded annually, after 4 years

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)

it is rigid.; it is isometric. ; the size is preserved.

step-by-step explanation:

a translation is called an isometry; these are transformations that preserve congruence between pre-images and images.

they are also called rigid transformations, as the only thing that can happen to a pre-image is that it is moved or turned, not stretched or shrunk.

since congruence is preserved, the size is preserved.