Heron's formula for the area of a triangle

Given a triangle with the following measurements,

Basis=$11$ cm, side 1 $= 11$ cm, side 2 $=7,5$ cm, height (h) $=7$ cm

calculate the area using the Heron's formula.

First we proceed to calculate the semiperimeter.

The information of the statement interpreted by our formula is:

$$a=11, b=11, c=7,5$$

Then we have: $p=\dfrac{a+b+c}{2}=\dfrac{11+11+7,5}{2}=14,75$

Applying it to Heron's formula:

$$A=\sqrt{p(p-a)(p-b)(p-c)}=$$ $=\sqrt{14,75 \cdot (14,75-11) \cdot (14,75-11) \cdot (14,75-7,5)}=38,5\ \mbox{cm}^2$

$$38,5 \ \mbox{cm}^2$$

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