Video: Unit Conversions Involving Light-Years

What is 240000 ly in megalight-years?

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Video Transcript

What is 240000 light-years in megalight-years?

Okay, so in this question, we’re being asked to convert between light-years and megalight-years. So let’s try to remember what the conversion is. We can recall that a megalight-year is defined as 1000000 light-years because the prefix mega represents 1000000 or 10 to the power of six. And so, what we can do is to divide both sides of the equation by 1000000 so that it cancels on the right-hand side. And we’ve got light-years now in terms of megalight-years.

Tidying things up a little bit, we see that one millionth of a megalight-year is equivalent to one light-year. And so we want to find out what’s equivalent to 240000 light-years. We can do this by multiplying both sides of the equation by 240000 because this way on the right-hand side, we’ve got one light-year multiplied by 240000, which is the same thing as 240000 light-years. And on the left, we’ve got 240000 divided by 1000000 megalight-years.

But then the fraction simplifies to 0.24. And so we have on the left 0.24 megalight-years.

Hence, our answer to the question is that 240000 light-years in megalight-years is 0.24 megalight-years.