5. Isosceles and Equilateral Triangles
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Consider the Isosceles Triangle Theorem.
m∠ LMP=80
Looking at the given diagram, we see that LM≅ LP.
| Classification of Triangles | |
|---|---|
| Scalene Triangle | A scalene triangle is a triangle in which all three sides have different lengths. |
| Isosceles Triangle | An isosceles triangle is a triangle that has two congruent sides and two base angles with the same measure. |
| Equilateral Triangle | An equilateral triangle is a triangle in which all the sides are congruent. |
| Acute Triangle | An acute triangle is a triangle where all angles are less than 90^(∘) or π2. |
| Obtuse Triangle | An obtuse triangle is a triangle with exactly one an angle whose measure is greater than 90^(∘) or π2. |
| Right Triangle | A right triangle is a specific type of triangle that contains one angle of 90^(∘). |
Since the given triangle has two congruent sides, triangle LMP is an isosceles triangle. We want to find m ∠ LMP. To do so, we will consider the Isosceles Triangle Theorem.
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Isosceles Triangle Theorem |
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If two sides of a triangle are congruent, then the angles opposite those sides are congruent. |