This chart provides answers and hints. Try to reason about the properties on your own and use hints only as the last resort. If the answer is YES or NO, make sure to write down a complete proof - hints only provide general ideas that you need to supplement it with all necessary details. If the answer is SOMETIMES, provide examples and counterexamples. For the area formulas, provide a clear justification.

Fill out each row from left to right (and top-down). Anything you prove can be used in the following boxes (to the right or above). This also means that to prove a property you can only assume things that are to the left of (or above) the box you are working on. You may also need to consult our minimal definitions of quadrilaterals and the guide for filling out this form.

 

 

SIDES

ANGLES

DIAGONALS

AREA

Parallel?

Congruent?

Congruent?

Relationship?

Congruent?

Bisecting?

Perpendicular?

Triangle Partition?

Kite

Sometimes

Yes – 2 pairs of adjacent sides

Yes – (at least) one pair of opposite angles. Can you specify which pair of opposite angles is congruent? HINT

Nothing remarkable
Sometimes pairs of angles are supplementary

Sometimes

Yes – One diagonal always bisect the other HINT

Yes   HINT

Two pairs of congruent triangles. For concave kites, these triangles are fully or partially  "outside "the kite.

(d1 + d2)/2
HINT

Trapezoid

Yes – (at least) one pair

Sometimes

Sometimes

2 pairs of adjacent supplementary angles

HINT

Sometimes

Sometimes

Sometimes

One pair of triangles is similar. The other pair of triangles has the same area.

HINT

((h (b1 + b2))/s

HINT  

Isosceles Trapezoid

Yes – (at least) one pair

Yes – one pair of opposite sides. Can you specify which pair? HINT

Yes – 2 pairs of angles adjacent to the bases.

2 pairs of adjacent supplementary angles

HINT

Yes

HINT

Sometimes

Sometimes

One pair of triangles is similar. The other pair of triangles is congruent.
HINT

        ((h (b1 + b2))/2

Parallelogram

Yes – two pairs

Yes – 2 pairs of opposite sides HINT

Yes – 2 pairs of opposite angles HINT

Adjacent angles are supplementary

(Hint - see the box above)

Sometimes

Yes
HINT

Sometimes

Two pairs of congruent triangles.

HINT

b h

 

HINT

Rhombus

Yes – two pairs

HINT

Yes – all sides

Yes – 2 pairs of opposite angles

HINT

Adjacent angles are supplementary

(Hint - see the boxes above)

Sometimes

Yes

(Hint - Can you apply hint from parallelograms to rhombi?)

Yes

HINT

or Can you apply the hint from kites to rhombi?

All triangles are congruent

(Apply the previous hint (left box))

 b h

Rectangle

Yes – two pairs

HINT

Yes – two pairs of sides

HINT or try to apply the hint from Parallelograms

Yes – all angles

HINT

Any two angles are supplementary

(Hint - see the previous box)

Yes

(Can you apply the hint from isosceles trapezoids?)

HINT

Yes

(Can you apply the hint from parallelograms?)

Sometimes

Two pairs of congruent triangles.

(Can you apply the hint from parallelograms?)

l w 

Square

Yes – two pairs

(Hint - see Observation 1 in the hint for rhombi)

Yes – all sides

Yes – all angles

HINT

Any two angles are supplementary

Yes

(Can you apply the hint from isoscleles trapezoids or rectangles?)

Yes

(Can you apply the hint from parallelograms?)

Yes

(Can you apply the hint from kites or rhombi?)

All triangles are congruent

(Can you apply the hint from rhombi?)

s^2