Hey guys i need , i'm using my friends account because i don't have a phone and i have a retake quiz because everyone completely failed. !

Set up a proportion (2 fractions equal to each other)

One fraction will be based on the scale given. 
4cm = 5km, which can be written as 4/5  (Note: cm is on top)

The 2nd fraction will be used to find unknown variable.
You are given 4km and asked what distance on map does it represent?
X cm = 4km , or x/4     (Note: cm is on top)

Write the proportion:

Solve for x:
-multiply by 4 on both sides

 3.2 cm = 4 km

Part b)  Use same process, 1st fraction is still 4/5
For 2nd fraction you are given 5cm = X km,  5/x

Write proportion:

Solve for x:
- Get the 'x' out of denominator, take reciprocal of both sides

-Multiply by 5 on both sides

5cm = 6.25 km