Question

Sides of a triangle are in the ratio 3:4:5 and its semi perimeter is 18 cm. find its area

Answer 1

Semi perimeter = perimeter/ 2. Ratio of sides = 3:4:5 which = 3x+4x+5x = 12x.
Sum of all three i.e 12 x = 18*2. Therefore x = 3. Sides are :-
9,12 and 15cm.
Area = 1/2 x base x height.

Here base and height are smaller sides 9 and 12. (Pythagoras theorm)

Hence area = 9 * 12 / 2 = 54 cm^2.

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