Note that triangle ABD is a 6-8-10 Pythagorean Triple Right Triangle
And triangle ABD is similar to triangle CDA...so
AD / BD = CA / DA ....so....
10/ 8 = CA / 6 multiply both sides by 6
60 / 8 = CA = 7.5
So.....the area of ABC = (1/2) (AB) (AC) = (1/2)(10(7.5) = 37.5 units^2