Answer:
Use Heron's formula; see below.
Step-by-step explanation:
Use Heron's formula.
Let the sides of the triangle have lengths a, b, and c.
[tex] s = \dfrac{a + b + c}{2} [/tex]
[tex] area = \sqrt{s(s - a)(s - b)(s - c)} [/tex]
Example:
A triangle has side lengths 3, 4, and 5 units.
Find the area of the triangle.
[tex] s = \dfrac{a + b + c}{2} [/tex]
[tex] s = \dfrac{3 + 4 + 5}{2} [/tex]
[tex] s = 6 [/tex]
[tex] area = \sqrt{s(s - a)(s - b)(s - c)} [/tex]
[tex] area = \sqrt{6(6 - 3)(6 - 4)(6 - 5)} [/tex]
[tex] area = \sqrt{6(3)(2)(1)} [/tex]
[tex] area = \sqrt{36} [/tex]
[tex] area = 6 [/tex]
