What is the area of a triangle with sides 8 cm, 8 cm, and 4 cm?

Step 1: Set up formula to calculate a area of the Isosceles triangle.
FORMULAS:
1) Area of an isosceles triangle = \frac{1}{2} b*h
Where b - base and h - height (altitude)
h (Altitude) = \sqrt{a^2 - \frac{b^2}{4}}
When Two equal sides – s & s & included angles
2) Area of an isosceles triangle = \frac{1}{2}*s^2*\sin\theta
s is the length of one of the two equal sides.
θ is the angle between the two equal sides.
Step 2: According to the given data choose the appropriate formula to find the area
NOTE: In the question the lengths of the triangle are given so use first formula.
Step 3: Calculate the height of the triangle.
EXAMPLE: h(Altitude)=\sqrt{a^2-\left(\frac{b}{2}\right)^2}
height {\displaystyle h={\sqrt {8^{2}-({\frac {4}{2}})^{2}}}}
{\displaystyle ={\sqrt {64-4}}}
{\displaystyle ={\sqrt {60}}}
Simplify the square root by finding factors:
{\displaystyle h={\sqrt {60}}={\sqrt {4*15}}={\sqrt {4}}{\sqrt {15}}=2{\sqrt {15}}.}
Step 4: Plug the base and height into your area formula.
EXAMPLE: Area {\displaystyle ={\frac {1}{2}}bh}
{\displaystyle ={\frac {1}{2}}(4)(2{\sqrt {15}})}
{\displaystyle =4{\sqrt {15}}}
Leave this answer as written, or enter it in a calculator to find a decimal
estimate (about 15.49 square centimeters).