Answer:
28 units³
Step-by-step explanation:
The volume (V) of the prism is calculated as
V = Al ( A is the area of end face and l is the length )
Here A =
and l =
, thus
V =
×
( cancel 21 and 3 by 3 and 2 and 8 by 2 )
=
×
= 7 × 4 = 28 units³
Because ABCD is an isosceles trapezoid, the angles A and D are congruent.
BA and CD are congruent (given) and AD is congruent to itself (reflexive property).
Then triangles BAD and CDA form a pair of SAS triangles, so they are congruent.
BD and CA are corresponding parts in those triangles, so they are congruent (CPCTC).