Question

Question 7 of 27

A DEF is a dilation of A ABC by a scale factor of . Which of the following
proportions verifies that A ABC and ADEF are similar?
B
15
12
A 30
9
о
A.
AB
AC
DE
EF
O
B.
AC
DF
O
c.
DE
BC
EF
E PREVIOUS
arch

Answer 1

9514 1404 393

Answer:

B. AB/DE = AC/DF

Explanation:

When triangles are similar, corresponding sides have the same ratio. We are told that ∆ABC ~ ∆DEF. This means that corresponding sides are ...

AB : DE

BC : EF

AC : DF

Any pair of these ratios can be used to write the proportion. Each proportion can be written in 4 different ways. The answer choices show that AB and DE are involved in the proportion we want, so we can have any of ...

AB/DE = BC/EF

AB/DE = AC/DF . . . . . . matches choice B

AB/AC = DE/DF

_____

Additional comment

When we say a proportion can be written 4 ways, we mean all of these versions of a proportion are fully equivalent:

• a/b = c/d
• a/c = b/d . . . . sideways
• b/a = d/c . . . . upside down
• c/a = d/b