Answer: If four numbers are proportional, a : b = c : d, then the product of the extremes is equal to the product of the means. ad = bc
 
        
             
        
        
        
Answer:
<h2>
Average speed is 15km/h</h2>
Step-by-step explanation:
Step one:
given data:
total distance =7.5km
time taken= 30 min= 0.5 hours
we know that the average speed is the average distance divided by time taken
Step two:
mathematically expressed as 
speed=distance/time
substituting we have
speed=7.5/0.5
speed=15km/hour
Hence the average speed is 15km/h
 
        
             
        
        
        
Here is a video to help you with your question:
https://youtu.be/WaeD3qKc7Jc 
 
        
             
        
        
        
To convert a pexent to a decimal you have to multiply by 100. 
Move the decimal: Another way to convert from decimal to percentage format is to move the decimal two places to the right.
Hope this helped :)
Have a good day