In the given figure, ABCD is a parallelogram, AE ⊥DC and CF ⊥ AD. If AB = 18 m, AE =10m and CF =12 m, then find the length of AD.

We know that,

Area of parallelogram = Base × Altitude

∴ Area of parallelogram ABCD = DC× AE

= 18×10…(i)

[∵ DC = AS = 18m, AE = 10 m]

Again, area of parallelogram ABCD = AD ×CF

= AD × 12…(ii)

From Eqs. (i) and (ii), we get

18 ×10 = AD ×12