A masonry dam has a trapezoidal cross section, 25m high, crest width 3 m and base length 18 m. The upstream face slopes down 12 m in 25 m and the downstream face slopes down 3 m in 25m . If water at the upstream face stands flushed with the crest, and assuming no hydrostatic uplift, compute : (a) F. S. vs. O. T.;(b) soil pressures at the heel and toe of the dam; (c) Location of the point along the base where the resultant force intersects it. (Specific gravity of concrete is 2.40).