Question

Need help with this problem ... triangle ABC is similar to triangle DEF BR=RC ES=SF

1. if BC=24 EF=15 AR=x DS=x-16, find x

2. if ED=11 EF=12 DF=9 AC=20, find perimeter of ABC

got 42.6 for #1 and 71 for 2 but not so sure

Answer 1

well for question 1 its a case of using the ratio of corresponding sides in similar triangles are equal..

so

\[\frac{15}{24} = \frac{x - 16}{x}\]

I'd cross multiply and then solve for x.

and the answer to question 1 is correct

Question 2

you need to find AB and BC by looking at ratios of corresponding sides

\[\frac{20}{9}=\frac{BC}{12}\]

and

\[\frac{20}{9} = \frac{AB}{11}\]

and the answer for 2 seems fine