Classification of Triangles

A triangle with three sides of equal length could be:

Obtuse Any of the above Right Equilateral

Two angles in a triangle measure 100° and 40°. Is the triangle isosceles?

No Yes

If one of my angles measures 50°, what type of triangle could I be?

Right Obtuse All of the above Isosceles Acute

Will the three pencils with lengths of 3, 4, and 6 create an acute, right, or obtuse triangle?[br][img]https://ds055uzetaobb.cloudfront.net/brioche/uploads/05Bx675cMC-group-72.svg?width=240[/img]

Right Obtuse Acute

Is this triangle isosceles?[br][img]https://ds055uzetaobb.cloudfront.net/brioche/solvable/2a9b37250c.2e51935d77.FIaJbg.png?width=250[/img][br]

Yes No

What type of triangle has both an 89° angle and a 1° angle?

Acute Obtuse Right Isosceles

Two sides of an isosceles triangle measure 3 and 5. What could be the length of the third side?

1 4 2 3

[img]https://ds055uzetaobb.cloudfront.net/brioche/uploads/OvpnwjRacP-group-63.svg?width=250[/img][br]Above, a line cuts across two adjacent rectangles.[br]How many right triangles can you find in this diagram?

2 4 1 3

[img]https://ds055uzetaobb.cloudfront.net/brioche/solvable/4ec7e5a849.4ba2562095.mB6MKD.png?width=250[/img][br]If [math]\angle A = 45 ^\circ[/math], [math]\angle B = 35 ^\circ[/math] and [math]\angle C = 100 ^\circ[/math] in the above triangle, what type of triangle is [math]\triangle ABC[/math]?

acute triangle regular triangle right triangle obtuse triangle

[img]https://ds055uzetaobb.cloudfront.net/brioche/solvable/4ec7e5a849.109696b53e.yUmo5W.png?width=250[/img][br]The length of [math]\overline{AB}[/math] is the same as that of [math]\overline{AC} [/math][br] in the above triangle. If [math]\angle B =74^\circ[/math], what is [math]\angle C[/math]?

[math]76^\circ[/math] [math]78^\circ[/math] [math]72^\circ[/math] [math]74^\circ[/math]

[img]https://ds055uzetaobb.cloudfront.net/brioche/solvable/4ec7e5a849.a61883a66e.rbW8d5.png?width=250[/img][br]Suppose that [math]\angle A = 80 ^\circ[/math], [math]\angle B = 55^\circ[/math] and \angle C = 45^\circ[/math]. If points [math]D[/math], [math]E[/math] and [math]F[/math] are the midpoints of [math]\overline{BC}[/math], [math]\overline{CA}[/math] and [math]\overline{AB}[/math], respectively, what type of triangle is [math]\triangle DEF[/math]?[br][br][b]Note:[/b] The above diagram is not drawn to scale.

right triangle regular triangle obtuse triangle acute triangle

What do we call a triangle which has exactly 2 equal angles?

isosceles triangle right triangle equilateral triangle acute triangle

Classification of Triangles

Information: Classification of Triangles