From the graph fo angle of deviation `delta` versus angle of incidwence `i`. Find the prism angle

Explanation

From the graph ,
`delta I + e - A`
`30^(@) = 30^(@) + 60^(@) - A`
`:. A = 60^(@)` ltbrZgt (Use the result : If `i` and `e` are interchanged then we get same value of `delta`)