Answer :
Im thinking there are two ways....
8² +1² = 8 * 8 + 1 *1 = 64 + 1 = 65
7² + 4² = 7 * 7 + 4 * 4 = 49 + 16 = 65
8² +1² = 8 * 8 + 1 *1 = 64 + 1 = 65
7² + 4² = 7 * 7 + 4 * 4 = 49 + 16 = 65