Answer:
50 km
Step-by-step explanation:
Given
[tex]r = 4cm : 20km[/tex] -- Scale ratio
Required
Actual representation of 10cm
Let the actual measurement be x.
So, we have:
[tex]r =10cm:x[/tex]
Equate both value s of r
[tex]10cm : x = 4cm : 20km[/tex]
Express as fraction
[tex]\frac{x}{10cm } =\frac{20km}{4cm}[/tex]
Multiply by 10cm
[tex]10cm * \frac{x}{10cm } =\frac{20km}{4cm} *10cm[/tex]
[tex]x =\frac{20km}{4} *10[/tex]
[tex]x =5km *10[/tex]
[tex]x =50\ km[/tex]