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Which classification best represents a triangle with side lengths 6 cm, 10 cm, and 12 cm? 1. acute, because 62 + 102 < 122 2.acute, because 6 + 10 > 12 3.obtuse, because 62 + 102 < 122 4.obtuse, because 6 + 10 > 12

1 Answer

3 votes

Answer:

The best represents a triangle is obtuse, because 6 + 10 > 12 ⇒ answer 4

Explanation:

* Lets talk about some facts in the triangle

- The triangle is formed when the sum of the lengths of the shortest

two side is greater then the length of the longest side

∵ The lengths of the sides are 6 cm , 10 cm , 12 cm

∵ 6 + 10 > 12

∴ 6 , 10 , 12 are the sides of a triangle

- Two know the type of the triangle use these rules

# The three sides of the triangle have lengths a , b , c where a and b

are the shortest sides means a , b < c, then

- If a² + b² > c² , the triangle is acute triangle (its 3 angles are acute)

- If a² + b² = c² , the triangle is right triangle (the angle opposite to c is a

right angle and the other 2 angles are acute angles)

- If a² + b² < c² , the triangle is obtuse triangle (the angle opposite to c is an

obtuse angle and the other 2 angles are acute angles)

∵ (6)² + (10)² = 36 + 100 = 136

∵ (12)² = 144

∵ 136 < 144

∴ (6)² + (10)² < (12)²

∴ The triangle is obtuse

* The best represents a triangle is obtuse, because 6 + 10 > 12

User Mehdi Behrooz
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