Math Core

Unit 5 · Test

Unit 5 test: Congruent Triangles

15 questions. Answer them all, then submit to see your score. Solutions unlock after you submit.

This test covers congruence and rigid motions, the SSS, SAS, ASA, AAS and HL shortcuts, CPCTC, and isosceles and equilateral triangles.

Question 1

Given △ABC≅△RST\triangle ABC \cong \triangle RST, which angle is congruent to ∠C\angle C?

Question 2

Given △KLM≅△XYZ\triangle KLM \cong \triangle XYZ, KL=3x+2KL = 3x + 2 and XY=5x−8XY = 5x - 8. Find KLKL.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 3

△ABC\triangle ABC has vertex A(2,3)A(2, 3). It is reflected across the xx-axis to form the congruent triangle △A′B′C′\triangle A'B'C'. What are the coordinates of A′A'?

Enter a point like (2, -3)

Question 4

Which shortcut proves the triangles congruent?

Triangles ABC and DEF. Matching marks show congruent parts.
Question 5

In △PQR\triangle PQR and △STU\triangle STU, PQ‾≅ST‾\overline{PQ} \cong \overline{ST}, QR‾≅TU‾\overline{QR} \cong \overline{TU} and ∠R≅∠U\angle R \cong \angle U. What can you conclude?

Question 6

△ABC\triangle ABC has AB=5AB = 5, BC=12BC = 12 and m∠B=90∘m\angle B = 90^\circ. △DEF\triangle DEF has DE=5DE = 5, EF=12EF = 12 and m∠E=90∘m\angle E = 90^\circ. The triangles are congruent by SAS. Find DFDF.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 7

In △ABC\triangle ABC and △DEF\triangle DEF, ∠A≅∠D\angle A \cong \angle D, ∠B≅∠E\angle B \cong \angle E and BC‾≅EF‾\overline{BC} \cong \overline{EF}. Which shortcut proves the triangles congruent?

Question 8

△PQR≅△STU\triangle PQR \cong \triangle STU by ASA. m∠P=47∘m\angle P = 47^\circ and m∠U=58∘m\angle U = 58^\circ. Find m∠Qm\angle Q in degrees.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 9

Given: AB‾∥CD‾\overline{AB} \parallel \overline{CD}, and EE is the midpoint of AD‾\overline{AD}. Prove: △ABE≅△DCE\triangle ABE \cong \triangle DCE.

AB is parallel to CD. Segments AD and BC cross at E, the midpoint of AD.
StatementReason
1. AB‾∥CD‾\overline{AB} \parallel \overline{CD}Given
2. ∠BAE≅∠CDE\angle BAE \cong \angle CDE?
3. EE is the midpoint of AD‾\overline{AD}Given
4. AE‾≅DE‾\overline{AE} \cong \overline{DE}Definition of midpoint
5. ∠AEB≅∠DEC\angle AEB \cong \angle DECVertical angles are congruent
6. △ABE≅△DCE\triangle ABE \cong \triangle DCEASA

What is the missing reason in step 2?

Question 10

△JKL\triangle JKL and △MNP\triangle MNP are right triangles with right angles at KK and NN. JL‾≅MP‾\overline{JL} \cong \overline{MP} and KL‾≅NP‾\overline{KL} \cong \overline{NP}. Which shortcut proves △JKL≅△MNP\triangle JKL \cong \triangle MNP?

Question 11

△ABC≅△DEF\triangle ABC \cong \triangle DEF by HL, with right angles at BB and EE. The hypotenuse AC‾\overline{AC} has length 1010 and leg AB‾\overline{AB} has length 66. Find EFEF.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 12

In quadrilateral ABCDABCD, AB‾∥DC‾\overline{AB} \parallel \overline{DC} and AB‾≅DC‾\overline{AB} \cong \overline{DC}, and diagonal AC‾\overline{AC} is drawn, so △BAC≅△DCA\triangle BAC \cong \triangle DCA by SAS. If BC=3y−4BC = 3y - 4 and DA=y+10DA = y + 10, find BCBC.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 13

The vertex angle of an isosceles triangle measures 36∘36^\circ. What is the measure of each base angle, in degrees?

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 14

In △ABC\triangle ABC, AB‾≅AC‾\overline{AB} \cong \overline{AC}, m∠B=(5x−7)∘m\angle B = (5x - 7)^\circ and m∠C=(3x+17)∘m\angle C = (3x + 17)^\circ. Find m∠Am\angle A in degrees.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 15

An equilateral triangle has sides of length 4x+34x + 3 and 7x−97x - 9. Find its perimeter.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.