right angle triangle help

I need to make a program which calculates whether or not a triangle is a right angle triangle based on the input of the 3 sides. heres my code wondering if anyone can point out the errors?

Code:

`/* This program will calculate wether or not the values entered by a user consitute a right angle triangle*/`

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

int main()

{

float a, b, c;

int sum;

printf("please enter your values of length for the sides of your triangle.\n a and b will be the shorter sides while the value you enter for \nc must be the greatest length\n");

printf(" enter a:\n");

scanf("%f", &a);

printf(" enter b:\n");

scanf("%f", &b);

printf(" enter c:\n");

scanf("%d", &c);

sum = sqrt(a*a+b*b);

if (sum == c)

{

printf("your values indicate the triangle is a right angle triangle\n");

}

else

{

printf("The values entered do not indicate a right angle triangle\n");

}

system ("pause");

return 0;

}