Video Transcript
Find the perimeter of the shaded
region.
Part of the square grid that we can
see has been shaded in. And it makes this interesting
shape. This is the shaded region that the
question talks about. And in the question, we’re asked to
find the measurement of this region. We’re not asked to find the length
or the width or the height. We’re asked to find this shape’s
perimeter. What does the word perimeter
mean? A shape’s perimeter is the distance
all around it. So if we’re going to find the
perimeter of this shape, we’re going to need to decide where to start and then count
how many units or square lengths it takes to go all the way around back to where we
started. We can’t leave any gaps. It must be the complete
distance.
To make sure we remember where we
started, it makes sense to start from one of the vertices or corners of the
shape. Let’s start measuring from this
vertex here. Let’s count each unit together,
one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16,
17, 18. And we’re back where we
started. We know that the perimeter of a
shape is the distance all around it. And we found the distance all
around this shape by starting in a corner and counting all the unit lengths that go
all the way around. The perimeter of the shaded region
is 18 units.
