### Video Transcript

Emma is making a symmetrical
pattern. She has drawn her mirror line. What is the missing part of her
pattern?

We’re told that Emma has made a
symmetrical pattern and we can see a picture of it. Let’s remind ourselves what the
words symmetrical pattern mean. When something symmetrical, it’s
the same on both sides. That’s why the idea of a mirror is
really useful when we’re thinking about symmetry. A mirror reflects what’s in front
of it, and it looks the same on both sides. We’re told in the question that
Emma has drawn her mirror line. Can you see where it is? Here it is, let’s label it in a
bright color so it stands out for us.

Now, this mirror line is
important. It’s in the very center of Emma’s
pattern. And because Emma’s pattern is
symmetrical on either side of the mirror line, the shapes are the same. Up close, next to the mirror line
at the top, we have two yellow squares, and the next two shapes along are the
same. We have two blue triangles. Now, although Emma is making a
symmetrical pattern, she hasn’t quite finished it yet. There’s a part to her pattern
that’s missing, and we’re asked, what is the missing part of her pattern? We need to think of the shapes that
belong in this space.

Now, you may think it’s got
something to do with these two shapes that are at the bottom, the pink circle and
the blue triangle. And you know what? You’d be right. Now, it would be very easy to look
at these shapes and to think, “Well, it must be the same on both sides.” The answer’s got to be a pink
circle and a blue triangle. Well, if you think the answer is
this, you’re almost there, but the answer is not quite right. And we can see why if we put these
shapes into position. Can you spot the mistake? If we start from the mirror line,
just like before, and we compare the shapes on either side, we start with a blue
triangle on one side, but the shape on the other side doesn’t match. It’s not the same, and neither do
the next two shapes along.

Can you see what we need to do to
make the pattern symmetrical? You’ve got the right shapes, but
they’re not in the right order. The nearest shape to the mirror
line needs to be a blue triangle and then the pink circle. Can you see how the shapes match
now? The pattern is the same on both
sides of the mirror line. It’s symmetrical. The missing part of Emma’s pattern
is a blue triangle followed by a pink circle.