Warm Up Classify each angle as acute, obtuse, or right. 1. 2. 3.

Warm Up Classify each angle as acute, obtuse, or right. 1.2. 3. 4. If the perimeter is 47, find x and the lengths of the three sides. right acute obtuse x = 5; 8; 16; 23

Classifying Triangles Section 4-1

Classify Triangles by Angles By Angle Measures Acute Triangle Three acute angles

Classify Triangles by Angles By Angle Measures Equiangular Triangle Three congruent acute angles

Classify Triangles by Angles By Angle Measures Right Triangle One right angle

Classify Triangles by Angles By Angle Measures Obtuse Triangle One obtuse angle

Example: Classifying Triangles by Angle Measures Classify BDC by its angle measures. Classify ADC by its angle measures. Classify ABD by its angle measures.

Example: Classify FHG by its angle measures.

Classify Triangles by Sides By Side Lengths Equilateral Triangle Three congruent sides

Classify Triangles by Sides By Side Lengths Isosceles Triangle At least two congruent sides

Classify Triangles by Sides By Side Lengths Scalene Triangle No congruent sides

Example: Classifying Triangles by Side Lengths Classify EHF by its side lengths. Classify EHGby its side lengths.

Example: Classify ACD by its side lengths.

Example: Using Triangle Classification Find the side lengths of JKL.

Example: Find the side lengths of equilateral FGH.

Classify Triangles Given Vertices • Example: Classify ABC. A(2, 4), B(3, -1), C(-4, 3)

Lesson Quiz Classify each triangle by its angles and sides. 1. MNQ 2.NQP 3. MNP 4. Find the side lengths of the triangle. acute; equilateral obtuse; scalene acute; scalene 29; 29; 23

Warm Up Classify each angle as acute, obtuse, or right. 1. 2. 3.