A vertical tower[ab] is built in a horizontal field, c and d are two points in the field. The angle at b at the base of the tower is 90°, From c the angle of elevation of the top of the tower is Jacb| = 30°and from d the angle of elevation to the top of the tower is Jadb| = 40°. Find correct to two decimal places \text { i. }|d b| \text { ii. } \quad|b c| \text { iii. If }|d \bar{b} c|=115^{\circ} \text {, find }|d c| \text { correct to two significant figures. }

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