As shown in figure 1.57, two poles of height 8 m and 4 m are perpendicular to the ground. If the length of shadow of smaller pole due to sunlight is 6 m then how long will be the shadow of the bigger pole at the same time ?

Here PR and AC represents the smaller and bigger poles, and QR and BC represents their shadows respectively.
Given PR = 4m, QR = 6m , AC = 8m, BC = x
PRQ ~ ACB [ ∵Vertical poles and their shadows form similar figures]
PR/AC = QR/BC [ Corresponding sides of similar triangles]
4/8 = 6/x
x = 6×8/4
x = 12
Hence the length of shadow of the bigger pole is 12 m.