#include <iostream>
#include <cmath>
int main(void) {
double a = 5; // length of two equal sides
double base = 8;
double area = (1 / 2.0) * base * sqrt((a * a) - ((base * base) / 4));
std::cout << "Area of Isosceles Triangle = " << area;
}
/*
run:
Area of Isosceles Triangle = 12
*/