Grade 4 Math: Triangles

How many types of triangles can you name? No - small triangles, medium triangles, big triangles and extra-big triangles is not what we're looking for here. Nice try though.

4th GradeMath
Elementary and Middle School4th Grade
LanguageEnglish Language

Transcript

00:27

So the robber left another of his mysterious clues for the police…

00:31

…but this time, there was also a witness. [Sheriff inspecting the clue]

00:33

And while this witness has certainly narrowed down the shape of the culprit, the detective

00:38

work isn’t over yet.

00:40

This would all be pointless if the bank had…oh, we don't know…a security guard, but whatever. [Newspaper headline about the security of the bank]

00:44

So we know we're looking for a shape with three sides…and we know shapes with three

00:48

sides are called triangles.

00:50

But there are actually four different types of these clever shapes.

00:54

So the cops round up the usual ne’er-do-wells and…this guy….wait, who let this guy in? [Shapes lined up in a row]

01:01

He's clearly not a three-sided…ugh, y'know what, whatever…you can stay.

01:05

So let's check out our lineup. [Suspects folder]

01:07

First is the equilateral triangle.

01:09

He seems pretty regular, right?

01:11

And that’s not just because of his fiber intake.

01:14

It’s because an equilateral triangle is – yup – equal all around.

01:18

Every side has the exact same length --

01:20

-- and every angle is sixty degrees.

01:23

Whether he's on his feet, standing on his head or lying down, you'll always know when [The triangle in different positions]

01:27

you’re looking at an equilateral triangle.

01:29

Next up: The Isosceles Triangle.

01:31

He may try to fool you into thinking he’s equilateral, and if you’re not careful,

01:36

you could fall for his shenanigans.

01:37

That’s because while two of his sides and two of his angles are the same, one side is

01:42

decidedly different.

01:44

All things being equal, the isosceles triangle prefers things a little skewed… [Isosceles triangle intentionally making paintings lopsided]

01:48

But the real odd one of the bunch is this guy: The Scalene Triangle.

01:53

Like a goth kid at the prom, this triangle does everything it can to be different from [Girl dressed like a goth arrives at the prom]

01:57

other triangles out there.

02:00

Every side is a different length and every angle a different size.

02:03

There’s no telling what this non-conforming shape might do.

02:06

We've got our eye on him…

02:08

And finally we have –

02:09

- no, not him. [Octagon waving]

02:10

We don't even know why he's here.

02:11

We were just trying to be nice.

02:13

Go home, octagon... [Octagon looks unhappy and walks off]

02:14

Finally, we have…him.

02:16

The Right Triangle.

02:17

When you first meet him, you might think he’s kind of a square.

02:20

But don’t be fooled.

02:21

One of his angles is always ninety-degrees, but the rest of him is as triangular as they

02:26

come.

02:27

So which one of this quartet of triads has been identified as the Shapetown Stealer?

02:31

…Seriously?

02:32

See, if you had a security guard, this never would have been an issue… [Witness says it might have been a semicircle]

02:35

We're starting a Go Fund Me page for y'all… [Octagon walking away with the bag of money]