Question

If Chang jogs one lap around the inside track, how far does he jog

Answer 1

Answer: D. 1277

Explanation:

First you divide 553 by 395 : 553/395=1.4

Now that you have 1.4 , you multiply that times both 350 and 280.

280 • 1.4=392

350 • 1.4=490

Add up all the sides: 395+392+490=1277

Answer 2

836 m

Explanation:

Given that the tracks are similar, therefore, the ratio of the lenght of all corresponding sides of the inside track to the outside track are equal, and have the same scale factor.

Only 1 side of the inside track is given as 395 m. It corresponds to the side of the outside that measures 553 m. Therefore:

scale factor = 395:553 =
`(395)/(553) = 0.7`

Find the remaining two sides of the insider tracks by multiplying the lenght of the side of the outside tracks that corresponds to each by the scale factor.

Thus:

280*0.7 = 196 m

350*0.7 = 245 m

The remaining 2 side lengths of the inside tracks are 196 m and 245 m.

If Chang completes 1 lap around the inside tracks, he would have gone: 395 + 196 + 245 = 836 m.