Given: ST∥QR
Construct a perpendicular from Q on ST such that it meets ST on M and COnstruct a perpendicular from R on ST such that it meets ST at N.
Hence, QM⊥ST and RN⊥ST
Since, ST∥QR, perpendicular distance between two parallel lines is same
hence, QM=RN
Now, Area of triangle = 12base×height
A(△QSTA(△RST)=12QM×ST12RN×ST
A(△QSTA(△RST)=11 (Since, QM=RN)