Perimeter = the sum of all the sides. In this case, we know the ratio but not what each would be multiplied by, hence the variable.
6x + 8x + 10x = 96
24x = 96
x = 4
6(4) = 24
8(4) = 32
10(4) = 40
Check:
24 + 32 + 40 = 96 cm
Area = (base * height) / 2
Base = 32
Height = 24
(The base and height are interchangeable here, as we just have to make sure we're multiplying the legs of the triangle together and avoiding the hypotenuse.)
(32 * 24) / 2
768 / 2
384
Area = 384 cm^2
Hope this helps!