12 multiple-choice questions, progressively harder.
Convex quadrilateral ABCDABCDABCD has both pairs of opposite sides congruent. Its diagonals are congruent and perpendicular. Which proof order is valid?
Solution
Correct answer: D
Both opposite-side pairs congruent establish a parallelogram by a prior converse test.
In that family, congruent diagonals give rectangle and perpendicular diagonals give rhombus. The intersection of those families is square.
A parallelogram has congruent diagonals. In proving that it is a rectangle, why does SSS give equal consecutive angles?
Correct answer: B
Compare triangles DAB and CBA: the diagonals are the given equal third sides, AD and BC are congruent opposite sides, and AB is common.
SSS makes angles DAB and CBA corresponding and congruent. Their separate supplementary relationship then forces right angles.
Parallelogram ABCDABCDABCD has perpendicular diagonals meeting at OOO. Triangles AOBAOBAOB and AODAODAOD are compared to prove that it is a rhombus. Which information uses the parallelogram hypothesis?
Correct answer: C
A parallelogram has diagonals that bisect each other, giving BO equal to OD.
The common side AO and the given right angles then complete SAS. Without the midpoint equality the proof does not work.
A parallelogram has diagonal lengths 3t+83t+83t+8 cm and 5t−65t-65t−6 cm, where t>2t>2t>2. For which ttt does this information establish a rectangle?
Correct answer: A
A rectangle requires the parallelogram diagonals to have equal lengths.
This satisfies the domain and gives both diagonals length 29 cm.
In rhombus ABCDABCDABCD, angle BACBACBAC measures (2u+7)∘(2u+7)^\circ(2u+7)∘ and the whole angle at BBB measures (5u+13)∘(5u+13)^\circ(5u+13)∘. Find uuu.
The whole angle at A is twice the given half-angle. Consecutive angles are supplementary.
The whole angles at A and B are 82 and 98 degrees, which are valid and supplementary.
A convex quadrilateral has congruent, perpendicular diagonals. Which statement describes what can be concluded?
A square satisfies both conditions.
But perpendicular rays with lengths AO 4, OC 2, BO 3, and OD 3 give these whole lengths.
The unequal parts AO and OC prevent bisection. This convex quadrilateral is not a parallelogram, so the evidence does not guarantee square.
In a rectangle, a diagonal bisects one of its endpoint vertex angles. Which conclusion follows?
A rectangle is a parallelogram. A parallelogram whose diagonal bisects an endpoint angle is a rhombus.
The figure is therefore both rectangle and rhombus, so it is square.
A rhombus has whole diagonals of 161616 cm and 303030 cm. What is its side length?
The diagonals bisect each other and are perpendicular. The small right triangle has legs 8 cm and 15 cm.
Using whole diagonals as legs would produce the wrong hypotenuse 34 cm.
Convex quadrilateral ABCDABCDABCD has diagonals meeting at OOO. All four segments AOAOAO, BOBOBO, COCOCO, and DODODO have length 555 cm. No angle measure is given. What is guaranteed?
The four equal halves establish bisection of both diagonals, so the figure is a parallelogram.
Each whole diagonal contains two 5-centimeter halves.
Congruent whole diagonals establish a rectangle. The intersection angle need not be right; a rectangle with unequal adjacent sides is still possible.
Which biconditional is true for convex quadrilaterals?
For parallelograms, congruent diagonals characterize rectangles and perpendicular diagonals characterize rhombi.
Both properties therefore characterize squares within parallelograms. The unrestricted converses fail, and bisection alone holds in nonsquare parallelograms too.
A convex quadrilateral has one pair of opposite sides both parallel and congruent, and a diagonal bisects a whole angle at its endpoint. What is guaranteed?
The same opposite-side pair being both parallel and congruent establishes a parallelogram.
The diagonal angle-bisector test then establishes a rhombus. Right angles or equal whole diagonals have not been established, so a square is possible but not forced.
Which extra condition is sufficient to turn a known rhombus into a square?
A rhombus is a parallelogram. Congruent diagonals therefore make it a rectangle as well, giving square.
The other conditions are already true in every rhombus, including nonsquare ones.
Reset this practice set?
This clears every answer you have given and starts the set again from question 1.