IXL - Similar triangles and indirect measurement (Geometry practice)

Find j.

6 ft

4 ft

Write your answer as a whole number or a decimal. Do not round.

j = feet

ref_doc_title.

Learn with an example

question

In the diagram below,

PON

MOL. Find n.

5 ft

8 ft

10 ft

Write your answer as a whole number or a decimal. Do not round.

n = feet

key idea

The sides of similar triangles are proportional.

solution

The original diagram included a smaller triangle and a larger triangle. Redraw them as separate triangles with corresponding sides in the same color.

5 ft

8 ft

10 ft

PON

MOL means that

PON is similar to

MOL.

One
pair
of
corresponding
side
lengths
is
LM
and
NP
.
Together
they
form
the
fraction
LM
NP
.

Another
pair
of
corresponding
side
lengths
is
MO
and
PO
.
Together
they
form
the
fraction
MO
PO
.

In both fractions, the numerator comes from

MOL and the denominator comes from

PON. Since the triangles are similar, you can use the fractions to set up a proportion and solve for n.

Plug in the side lengths

(

)

(

)

Multiply both sides by 5n

Simplify

Divide both sides by 10

The missing length is 4 feet.

Looking for more? Try these:

Lesson: Similar triangles

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Not feeling ready yet? These can help:

M.4Side lengths and angle measures in similar figures

Lesson: Similar triangles

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