Question

Suppose triangle ABC can be taken to triangle A'B'C' using rigid transformations and a dilation. Select all of the equations that are true

A'C'/BA=AC/BA

B'C'/B'A'=BA/BC

AC/A'C'=B'A'/BA

CA/C'A'= CB/C'B'

A'B'/AB=C'B'/CB

Answer 1

The true equations are,

CA/C'A' = CB/C'B'

and,

A'B'/AB=C'B'/CB

Explanation:

Since we use a dilation, the length A'B' is not equal to AB and so on for the other lengths,

Since A'C' is not equal to AC (due to the dilation)

hence A'C'/BA does not equal AC/BA

hence the first option is false

B'C'/B'A' = BA/BC is false because a/b does not necessarily equal b/a (for example 3/4 is not equal to 4/3)

AC/A'C' = B'A'/BA ,collecting all terms of the same triangle on one side, we get,

1/(A'C')(B'A') = 1/(AC)(BA) but since A'C' = AC is false (due to dilation)

so, 1/(A'C')(B'A') = 1/(AC)(BA) is also false and AC/A'C' = B'A'/BA is also false

CA/C'A' = CB/C'B'

Collecting terms from the same triangle on either side, we get,

C'B'/C'A' = CB/CA

Now, since the ratios of the lengths do not change in a dilation, this relation is true

A'B'/AB=C'B'/CB

Collecting terms from the same triangle on either side, we get,

A'B'/C'B' = AB/CB

Now, since the ratios of the lengths do not change in a dilation, this relation is true