Explanation: Triangles can be classified based on their side lengths as follows: 1- (longest side)² = (first short side)² + (second short side)² .......> right Δ 2- (longest side)² > (first short side)² + (second short side)² .......> obtuse Δ 1- (longest side)² < (first short side)² + (second short side)² .......> acute Δ
let's perform this check on the given sets: 1- First set (4,5 and 7): 7² = 49 5² = 25 4² = 16 49 > 25 + 16 49 > 41 Triangle is obtuse
2- Second set (5,7 and 8): 8² = 64 7² = 49 5² = 25 64 < 49 + 25 64 < 74 Triangle is acute
3- Third set (6,7 and 10): 10² = 100 7² = 49 6² = 36 100 > 49 + 36 100 > 85 Triangle is obtuse
4- Fourth set (7,9 and 12): 12² = 144 9² = 81 7² = 49 144 > 81 + 49 144 > 130 Triangle is obtuse
