Vocab Terms
Error Analysis
Bisectors/Midsegments
Triangle Inequalities
Mix
100
The middle point of a line segment.
What is a midpoint?
100
Correct the student's answer.
Question: DE is a midsegment of ABC. Find x.
Answer: x = 52
The midsegment is half the side it is parallel to.
Correct answer: x=13
100
Is DE a midsegment of ABC? Why or why not?
Yes, because it splits both AB and AC into equal parts.
100
Is it possible to create a triangle with side lengths 20, 27, and 10? Show your work as an explanation.
Yes.
20+27>10 27+10>20 20+10>27
100
List the sides of the triangle from shortest to longest.
AB, BC, AC
200
An equal distance from a single point or object.
What is equidistant?
200
Correct the student's answer.
Question: Can the side lengths 20, 5, 15 form a triangle? Explain.
Answer: Yes because 20+5 > 15.
The student should have checked that the sum of EVERY two sides was greater than the third.
Correct answer: No.
200
Angle ABC is 96 degrees. What is the measure of angle ABD and angle DBC?
ABD = 48 degrees
DBC = 48 degrees
200
Triangle FGH has the following side lengths:
FG: 12
GH: 6
HF: 7
List the angles from smallest to largest.
Angle F, Angle G, Angle H
200
Find the measure of angle KJM.
KJM = 56 degrees
300
A segment connecting the midpoints of two sides of a triangle.
What is a midsegment?
300
What is the error in solving for SR? Find the correct length of SR.
The midsegment is not equal to the side it is parallel to.
SR = 6
300
The perimeter of an equilateral triangle ABC is 36 cm. What is the length of the midsegment that is parallel to side AC?
6 cm
300
A triangle has side lengths 20 and 24. What is the range of possible lengths for the third side?
4<x<44
300
Find EG. 
EG = 19
400
A line that divides an angle into two congruent angles.
What is an angle bisector?
400
Correct the student's answer.
Question: Triangle ABC has the following angle measurements: A = 67 degrees, B = 45 degrees, C = 68 degrees. Name the side lengths from longest to shortest.
Answer: AC, BC, AB
The student listed the side lengths from shortest to longest.
Correct answer: AB, BC, AC
400
VP is the angle bisector of XVW. If angle 2 = 1+28x and XVW = 59x - 1, find x.
x = 1
400
In ΔABC, AB = 4x + 2, BC = 5x - 3, and AC = 2x + 4. The perimeter of the triangle is 36 inches. Which angle in the triangle is the largest?
Angle C
400
Two sides of a triangle are 16 and 8. What is the range of possible side lengths for the third side?
8<x<24
500
A line that divides a segment into two equal parts and forms a right angle.
What is a perpendicular bisector?
500
Correct the student's answer.
Arithmetic error: x = 6.
Correct answer: VU = 55.
500
Find VW.
VW = 6
500
The perimeter of this triangle is 40 feet. Could these side lengths shown on the figure actually represent the sides of this triangle? Why or why not?
No. The sum of two of the side lengths is not larger than the third.
500
What is EG called in the diagram? Solve for FG. 
EG is the angle bisector.
FG = 16