長方形に内接することができる最大の三角形の面積はいくらですか?

#include  int main(void) { int l = 10, b = 9; float area ; area = (float)((l*b)/2); printf("Area of largest triangle inscribed in a rectangle of length %d and breadth %d is %f",l,b,area); return 0; }

Area of largest triangle inscribed in a rectangle of length 10 and breadth 9 is 45.000000