Video Transcript
Fill in the blanks. When measuring the length of an
object that a ruler must not or cannot directly touch, the positions of the opposite
ends of the object are blank. The object can then be blank and
the distance between the marked points can be measured with a ruler. Is it (A) exchanged and reversed or
(B) marked and removed?
In this question, we are asked to
figure out how we can measure the length of an object that a ruler must not or
cannot directly touch and fill in the blank spots to make the sentences correct.
Let’s recall some important
information when measuring with a ruler. Rulers are made from a straight
strip of material with markings that are spaced out carefully. The numbers on a ruler will always
start with zero and go to a greater value, increasing until the end of the ruler is
reached. To measure some length, the ruler
must be placed with its zero mark lining up with the end of the length being
measured. Because rulers are straight, they
must be set parallel to whatever length we are measuring in order to get an accurate
measurement.
Let’s go back to this problem and
look at the sentences we are trying to complete.
Looking at the blank spaces we need
to fill in, we are trying to think of a way we can measure the object without having
the ruler touch it. For the first blank space, if we
exchanged the positions of the ends of the object, our ruler still cannot touch
it. So this wouldn’t help us measure
the length of it. For the second blank space, if we
reversed the object, it would change the physical position of the object, but we
still would not be able to touch it with the ruler. So neither of the words in the
first option will work in these sentences.
Now let’s look at the words in the
second option we were given. If we mark the positions of the
opposite ends of the object, its length will be equal to the length between those
marks. And then, if we removed the object,
the marks of the ends of the objects would still be there. We could then use our ruler to
measure the length between the marks. And because the lengths of the
marks and the object are identical, we can measure the length of our object this
way.
Therefore, option (B), marked and
removed, is the correct answer.
