Answer
144$ unit^{2}$
Work Step by Step
Given a figure PQST
Lets draw perpendicular from T on base PQ at M and from S on QR at N
Then TSNM is a rectangle
and TS = MN = 12 therefore PM = 6 =NR
By Pythagoras theorem $\triangle$TMP
$TM^{2}$ = $10^{2}$ - $6^{2}$
= 100 - 36 = 64
TM = 8 units
similarly NS = 8 units
Area of parallelogram PQST = PQ*TM
=12 * 8 = 96 $unit^{2}$
Area of triangle SQR = $\frac{1}{2}$ * b * h = $\frac{1}{2}$ * 12 * 8
=48 $unit^{2}$
therefore total shaded area = 96 + 48 = 144$unit^{2}$