Find the area of a triangle whose sides are 42cm, 34cm and 20cm. - Vidyadip

Question

Find the area of a triangle whose sides are 42cm, 34cm and 20cm.

✓

Answer

Let a = 42cm, b = 34cm and c = 20cm
Now,
Semi-perimeter = $\text{s}=\frac{42+34+20}{2}$
$=\frac{96}{2}$
$=48\text{cm}$
Now,
Area of isoscale triangle $=\sqrt{\text{s}(\text{s}-\text{a})(\text{s}-\text{b})(\text{s}-\text{c})}$
$=\sqrt{48(48-42)(48-34)(48-20)}$
$=\sqrt{48\times6\times14\times28}$
$=\sqrt{6\times2\times2\times2\times6\times2\times7\times2\times2\times7}$
$=6\times2\times2\times2\times7$
$=336\text{cm}^2.$

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