1. The problem is to find the prime factors of 3899 using the tree method. 2. Start by testing divisibility by small prime numbers. 3. 3899 is not divisible by 2 (since it is odd). 4. Check divisibility by 3: sum of digits is 3+8+9+9=29, which is not divisible by 3, so 3899 is not divisible by 3. 5. Check divisibility by 5: last digit is not 0 or 5, so no. 6. Check divisibility by 7: 3899 ÷ 7 ≈ 557, but 7 × 557 = 3899 exactly, so 7 is a factor. 7. Now factor 557. 8. Check divisibility of 557 by small primes: 2 (no), 3 (5+5+7=17, no), 5 (no), 7 (7×79=553, no), 11 (11×50=550, no), 13 (13×42=546, no), 17 (17×32=544, no), 19 (19×29=551, no), 23 (23×24=552, no), 29 (29×19=551, no), 31 (31×18=558, no), 37 (37×15=555, no), 41 (41×13=533, no), 43 (43×13=559, no), 53 (53×10=530, no), 59 (59×9=531, no), 61 (61×9=549, no), 67 (67×8=536, no), 71 (71×7=497, no), 73 (73×7=511, no), 79 (79×7=553, no). 9. Since 557 is not divisible by any prime less than its square root (approximately 23.6), check 557 for primality. 10. Actually, 557 is a prime number. 11. Therefore, the prime factors of 3899 are 7 and 557. Final answer: $$3899 = 7 \times 557$$