What do you get if you cut a square along one of it's diagonals? What about cutting an equilateral triangle down one of its altitudes? Two special right triangles, that's what.

Objective 1a

You will be able to use properties of 45-45-90 right triangles to solve problems

Mr. Labelle explains a FoxTrot comic and then introduces the first special right triangle my cutting a square along one of its diagonal. Duration: 3_06

Objective 1b

When working through Investigation 1, don't just get a decimal approximation for each hypotenuse. You'll only see how special the 45-45-90 right triangle is if you simplify your radicals. Duration: 9_59

Objective 1c

You will be able to use properties of 30-60-90 right triangles to solve problems

Mr. Labelle completely avoids talking about Xenophilius Lovegood and the Deathly Hallows and jumps right into creating a 30-60-90 triangle by cutting an equilateral triangle down its altitude. Duration: 10_00

Objective 1d

Continuing with the previous investigation, we see that the hypotenuse is twice as long as the short leg in any 30-60-90 right triangle. But what about the longer leg? Duration: 9_59

Objective 1e

Here, we formalize the 30-60-90 Right Triangle Theorem, a favorite of the aforementioned Mr. Lovegood. Duration: 8_01

Objective 1f

In this final video, we look at two applications of the special right triangles, one of which is a beloved SAT problem. Duration: 8_35

Geometry 6(D) verify theorems about the relationships in triangles, including proof of the Pythagorean Theorem, the sum of interior angles, base angles of isosceles triangles, midsegments, and medians, and apply these relationships to solve problems

Geometry 7(B) apply the Angle-Angle criterion to verify similar triangles and apply the proportionality of the corresponding sides to solve problems.

Geometry 9(B) apply the relationships in special right triangles 30º-60º-90º and 45º-45º-90º and the Pythagorean theorem, including Pythagorean triples, to solve problems