Question

I have answer for the question it in the image but I don't know if it right and I don't know any other formulas to find the area of a triangle

Answer 1

Hello there. To solve this question, we'll have to remember which other formulas for area of triangles can be used.

Most specifically, it asks for a formula that works on an obtuse triangle, that is, a triangle that haves an angle that measures more than 90º.

Besides the formula BH/2, that refers to half of the product between the measurements of the base and the height of the triangle, of course, this height must be a projection perpendicular to the base, as in the following drawing:

Another formula that can be used is Heron's formula;

Knowing the measures of all the sides of the triangle (no matter if it is an obtuse, acute or right triangle), say a, b and c, Heron's formula states that the area S of the triangle is given by:

`S=√(\rho\cdot(\rho-a)\cdot(\rho-b)\cdot(\rho-c))`

Where

`\rho=(a+b+c)/(2)`

is the semiperimeter of the triangle.

This is the answer we've been looking for.