4.1 Classifying Triangles

Use the best description to classify the triangle. 

• acute

• equiangular

• obtuse

• right

Use the best description to classify the triangle.

• acute

• equiangular

• obtuse

• right

Classify

 $\Delta BDC$  as acute, equiangular, obtuse, or right. Explain your reasoning. 

• Acute, there are 30 degree angles.

• Equiangular, all three angles are 60.

• Right, angle ABC is 90 degrees.

• Obtuse,  $<BDC\$  is greater than 90 degrees. 

Classify the triangle as equilateral, isosceles, or scalene.

If K is the midpoint of segment FH, classify

 $\Delta FGH$  as equilateral, isosceles, or scalene. 

Find x and the measure of the unknown sides.

Enter your answer as:

x = #, LN = #, MN = #

Find x and the length of each side if

 $\Delta ABC$  is isosceles with  $\overline{AB}\ \cong\ \overline{BC}$  

Enter your answer as:
x = #, AB = #, BC = #, CA = #  

Classify  $\Delta EBC$  by its angles AND sides

• isosceles, acute

• isosceles, obtuse

• equilateral, equiangular

• scalene, acute

 $\Delta JKL$  is isosceles with  $\overline{JK}\cong\overline{KL}$  ,  $JK\ =\ 4x\ -1,\ KL\ =\ 2x\ +\ 5,\ LJ\ =2x\ -1.$  
Find x and the measure of each side. 

• x = 3; JK = 5, KL = 5, LJ = 11

• x = 1; JK = 3, KL = 7, LJ = 1

• x = 3; JK = 11, KL = 11, LJ = 5

• x = 0; JK = -1, KL = 5, LJ = -1

 $\Delta FGH\$  is an equilateral triangle with FG = 3x - 10, GH = 2x + 5, and HF = x + 20.
Find x. 

Enter your answer as:    x = #