IXL | Determine if two figures are congruent: justify your answer

The graph shows quadrilaterals

and

congruent to

Justify your answer.

Yes, because a reflection across the

-axis

maps

onto

Yes, because a rotation

clockwise around the origin maps

onto

No, because

and

do not have the same length.

No, because

∠

and

∠

do not have the same measure.

ref_doc_title.

Learn with an example

question

The graph shows triangles

and

congruent to

Justify your answer.

Yes, because a translation left 10 units and down 1 unit maps

onto

Yes, because a reflection across the

-axis

maps

onto

No, because

∠

and

∠

do not have the same measure.

No, because

and

do not have the same length.

key idea

Two figures are congruent if and only if one of them can be mapped onto the other by a sequence of rigid transformations: translations, reflections, or rotations.

Two figures are congruent if and only if all pairs of corresponding sides and angles are congruent.

solution

This sentence correctly states and justifies that

and

are congruent.

green checkmark, Yes, because a translation left 10 units and down 1 unit maps onto .

Translate left 10 units and down 1 unit to get . Notice that coincides with .

A reflection across the

-axis

does not map

onto

so this sentence is incorrect.

red X symbol, Yes, because a reflection across the -axis maps onto .

Reflect across the -axis to get . Notice that does not coincide with .

and

are congruent, so these sentences are incorrect.

red X symbol, No, because and do not have the same measure.

red X symbol, No, because and do not have the same length.

Looking for more? Try these:

Lesson: Congruence

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Not feeling ready yet? These can help:

R.13Describe transformations

R.15Sequences of congruence transformations: choose the sequence

R.16Identify congruent figures

Lesson: Congruence

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