The lengths of the sides of a triangle are in the ratio 3 : 4 : 5 and its perimeter is 144 cm. Find the area of the triangle and the height corresponding to the longest side.
Sides of triangle are in ratio: 3 : 4 : 5
Since the perimeter of a triangle is given by:
Therefore sides of the triangle are:
When a, b and c are the sides of triangle and s is the semi-perimeter, then its area is given by:
A = 
where 
[Heron’s Formula]
= 
= 72
A = 
A = 
= 
cm2
Area of triangle = 
864 = 
Altitude = 28.8 cm
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