Answer:
This is a complete lesson with instruction & exercises for 5th grade about multiplying decimals by decimals. The interpretation for multiplying a decimal by a decimal is to think of it as taking a fractional part of a decimal number (the symbol × translates to "of"). The lesson compares multiplication by a decimal to scaling & shrinking a stick. Lastly, it shows the common shortcut to decimal multiplication (multiply as if there were no decimal points; the answer has as many decimals as the factors have in total.)
In the video below, I explain the rule for multiplying decimals (put as many decimal digits in the answer as there are in the factors.) I explain where this rule comes from, using fraction multiplication. The lesson continues below the video.
9514 1404 393
Answer:
- k = 45 . . . miles per hour
- k = 1/45 . . . hours per mile
Step-by-step explanation:
One way we can relate distance and time is ...
time = k × distance
Then the value of k (the constant of proportionality) is ...
k = time/distance = 4 hours/(180 miles)
k = (1/45) hours/mile
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Another way we can relate the variables is ...
distance = k × time
Then the value of k (the constant of proportionality) is ...
k = distance/time = (180 miles)/(4 hours)
k = 45 miles/hour
I think c would be the correct answer
