Answer 1

Draw a perpendicular from Q to line MR. Where it meets the line MR name it point N. 
MN = PQ = 7 cm
In Δ PMS, 

PM² + SM² = PS²

⇒ 4² + 3² = PS²

⇒ PS² = 16 + 9 = 25

⇒ PS = 5cm 

PQRS is an isosceles trapezium so, PS = QR = 5 cm
PM = QN = 4 cm
So, NR = SM = 3 cm
SR = SM + MN + NR = 3 + 7 + 3 = 13 cm
Area of trapezium PQRS = `1/2 xx` (sum of parallel sides) x height 

=`1/2 xx` (7 + 13) x 4

= 40 cm²