Question

16. In Fig. 7.32, explain how one can find the breadth
of the river without crossing it.

Answer 1

here,

∠POQ=∠AOB  (alternate angle)

taking tan on both sides

tan(∠POQ)=tan(AOB)

or, PQ/OP=AB/OB

  or,PQ=AB              (OP=OB given)

∴PQ=AB

so, breadth of the river can be found by measuring length PQ