Find the area of the trapezium PQRS with height PQ given in Fig. 12.3
We draw perpendicular from R on PS, which is also parallel to PQ.
PQRT is a rectangle.
ST = PS – TP
ST = 12 – 7 = 5m (TP = RQ = 7m)
In Δ RTS,
RS2 = ST2 + RT2
⇒ 132 = 122 + RT2
⇒ 169 = 144 + RT2
⇒ RT2 = 169-144
⇒ RT2 = 25
⇒ RT = 5m
Area (PQRS) =
Area(PQRS) =
Area(PQRS) = 9.5 × 5 = 47.5 m2