Given 6, 8, and 11 as the three sides of a triangle, classify it as one of the following acute, right or obtuse. Please help and
1 answer:
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Answer:
obtuse
Step-by-step explanation:
You may remember that side lengths of 3, 4, 5 make a right triangle. Doubling those lengths to 6, 8, 10 will still give a right triangle.
The given triangle has a longest side (11) longer than would be appropriate for a right triangle (10), so the largest angle is larger than 90°.
The triangle is obtuse.
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Comparison of a triangle to a right triangle with two sides the same is one of several ways the triangle can be classified. You can use the Law of Cosines to find the largest angle, or you can use a triangle solver (as we have below).
In case you don't recall that 3-4-5 makes a right triangle, you can use the Pythagorean theorem to find the longest side of a right triangle with the given shorter sides:
hypotenuse = √(6² +8²) = √100 = 10
Your long side is longer, so your largest angle is larger than 90°.
Law of Cosines:
angle = arccos((6² +8² -11²)/(2·6·8)) = arccos(-21/96) ≈ 102.6°
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