### Video Transcript

There is a mystery shape in this
bag. Which clue will not help you guess
the name of the shape? It has five corners, it is green,
or it has five straight sides. Based on these clues, what is the
shape in the bag? Is it a square, a triangle, or a
pentagon?

Are you feeling like a shape
detective? Well, you’re going to need to be
one with this question because we’re told we have a mystery shape in the bag. And like any detective, we’re given
some clues to help us solve the problem. But not all of the three clues are
useful. We’re asked, which clue will not
help you guess the name of the shape? Now, all these clues are true about
our shape, but not all of them are useful. The first clue talks about the
number of corners that our shape has. The second clue talks about its
color. And our third clue talks about the
number of straight sides that it has. Which one of these clues isn’t very
useful at all?

It’s the color, isn’t it? Knowing the color of a shape
doesn’t help us tell what it is. Some circles are green, some
triangles are green, any shape at all could be green. Knowing that the shape is green is
not going to help us at all. If we want to be true shape
detectives, we need to use clues like the number of corners that a shape has, and
here we’re told that it has five corners, and also the number of straight sides that
it has, and we’re told that it has five straight sides. In the second part of the question,
we need to put these clues to the test.

Based on these clues, what is the
shape in the bag? Is it a square, a triangle, or a
pentagon? Now, one shape might jump out
straightaway as being wrong. We can see straightaway that the
triangle is the only shape that isn’t green. So we do know that the answer is
not going to be the triangle. But it would be a shame if we cross
the triangle off our list straightaway just because it was the wrong color. As we’ve said already, the color of
a shape isn’t something we can rely on.

So let’s think of our two clues
that really matter. It has five corners, and it has
five straight sides. How many corners does a square
have? One, two, three, four corners, not
five. And we also know that a square has
one, two, three, four straight sides, not five. The shape in the bag is not the
square. As we’ve already said, we know that
the shape isn’t the triangle cause it’s red. But let’s look at the more
important clues. Triangles have three corners, not
five, and three sides, not five.

This only leaves us with the
pentagon. A pentagon, it’s a shape that has
one, two, three, four, five corners. And we can count one, two, three,
four, five straight sides. Of course, the pentagon is green as
well. But it’s not this clue that helped
us. As any good shape detective knows,
we can tell a shape by the number of straight sides that it has and the number of
corners or vertices that it has. The clue that did not help us guess
the name of the shape was, it is green. So we used the remaining two clues,
it has five corners and it has five straight sides, to help us identify the mystery
shape as the pentagon.