12 multiple-choice questions, progressively harder.
In triangle ABCABCABC, an exterior angle at A measures 130∘130^\circ130∘. The other givens are:
Triangle DEFDEFDEF has these givens:
Which criterion establishes congruence in the listed order?
Solution
Correct answer: D
The interior angle at A and its exterior angle form a straight angle:
AB and DE join the matching 50-degree and 72-degree vertices. ASA establishes:
Two triangles have these given matching parts:
The included angles measure (4x−9)∘(4x-9)^\circ(4x−9)∘ and (2x+17)∘(2x+17)^\circ(2x+17)∘. What xxx makes the given information an SAS match?
Correct answer: B
Equate the included angles:
This gives
Both angle measures are
Both angles measure 43 degrees, so this is a valid included angle.
For SAS, one side pair already matches and the included angles both measure 75∘75^\circ75∘. The remaining side lengths are 2x+72x+72x+7 cm and 3x−43x-43x−4 cm. Which result completes the criterion?
Correct answer: C
Set the remaining pair equal:
Subtract 2x and add 4, giving
Substitution in either expression gives
Both sides are positive, so SAS applies with the stated angle and other side pair.
The intended ordered conclusion is △ABC≅△DEF\triangle ABC\cong\triangle DEF△ABC≅△DEF.
Given AB=DEAB=DEAB=DE, which set of additional facts directly completes an SAS argument?
BC=EFBC=EFBC=EF
∠B≅∠E\angle B\cong\angle E∠B≅∠E
∠A≅∠D\angle A\cong\angle D∠A≅∠D
AC=DFAC=DFAC=DF
AC=EFAC=EFAC=EF
Correct answer: A
The added side pair is:
With the given AB=DEAB=DEAB=DE, the known sides meet at B and E. Their required included-angle pair is:
The other choices either use a nonincluded angle or break the proposed correspondence.
Triangle ABCABCABC has these angle measures:
An exterior angle at C measures 132∘132^\circ132∘. Triangle DEFDEFDEF has these givens:
What value of xxx makes the ASA data match in the listed order?
The exterior angle equals the sum of the two remote interior angles.
Thus
Subtract 24 and divide by 3:
This gives angles A and B of 50 and 82 degrees, matching D and E.
AB and DE are the included sides, so ASA applies.
A positive base is to have endpoint angles (2t+10)∘(2t+10)^\circ(2t+10)∘ and (t+20)∘(t+20)^\circ(t+20)∘, where t>0t>0t>0. For which values of ttt do these data construct a triangle?
0<t0<t0<t
t≤50t\le50t≤50
t<60t<60t<60
t<50t<50t<50
For t>0t>0t>0, both proposed angles are positive. Their sum must be less than 180 degrees:
Solving gives:
Combining this with the given domain gives:
At t=50t=50t=50, the third angle would be zero.
Use this proposed correspondence:
The report gives:
Which assessment of a direct SAS argument is correct?
AB and AC meet at A, while DE and DF meet at D.
SAS with these side pairs requires
The angle pair at C and F is not that included pair.
This says the stated direct SAS argument is incomplete, not that the triangles must be noncongruent.
In the ASA motion proof, the bases have been aligned, but the third vertices are in opposite half-planes. Why must the possible reflection be considered before claiming the angle rays coincide?
The measure fixes a direction only after the opening half-plane is chosen. Reflection in the base aligns that choice while fixing its endpoints. The matching rays have a unique intersection, so the two candidate third vertices satisfy C′=FC'=FC′=F.
Triangle ABCABCABC has vertices A(0,0)A(0,0)A(0,0), B(4,0)B(4,0)B(4,0), and C(0,7)C(0,7)C(0,7). Triangle DEFDEFDEF has vertices D(2,1)D(2,1)D(2,1), E(2,5)E(2,5)E(2,5), and F(−5,1)F(-5,1)F(−5,1). Which argument establishes congruence in that order without finding the slanted side lengths?
AB=4AB=4AB=4
DE=4DE=4DE=4
AC=7AC=7AC=7
DF=7DF=7DF=7
The included angles at A and D are right angles.
Read horizontal and vertical segment lengths from the coordinate differences.
AB and DE each have length 4.
AC and DF each have length 7.
At A and D, a horizontal side meets a vertical side, so both included angles are right.
Those two side pairs and their included angles give
A pair of right angles alone would not fix the side lengths or establish congruence.
The given angle measures are:
The given side lengths are:
Can triangles JKL and MNP be congruent under that correspondence?
Congruence under this correspondence would require
But the stated lengths are 5 cm and 6 cm.
Rigid motions preserve length, so this proposed match is impossible even though the angle pairs agree.
Two successful constructions share a base of length 888 cm. Both use a second side of 555 cm from the left endpoint and an included angle of 42∘42^\circ42∘, but their third vertices lie on opposite sides of the base. How do the results compare?
The constructions have the same two sides and included angle, so SAS gives congruence.
Reflection in the base fixes both endpoints and sends the 42-degree ray to its partner.
The point 5 cm along that ray becomes the other third vertex:
The known matching parts are:
Which pair of plans correctly describes two different ways to finish a congruence argument?
Add AC=DFAC=DFAC=DF for SAS.
Or add ∠B≅∠E\angle B\cong\angle E∠B≅∠E for ASA.
Add BC=EFBC=EFBC=EF for SAS.
Or add ∠C≅∠F\angle C\cong\angle F∠C≅∠F for ASA.
Add AC=EFAC=EFAC=EF for SAS.
Or add ∠B≅∠F\angle B\cong\angle F∠B≅∠F for ASA.
For SAS, AC and DF meet the existing sides at the already matched angle vertices A and D.
For ASA, adding the angles at B and E puts the existing sides between the two angle pairs.
Either valid plan gives
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