How do you find out if this triangle is a right triangle?

7 ft14 ft

16 ft

In this lesson, you will learn how to classify a triangle by

using the Pythagorean Theorem.

Let’s ReviewLet’s Review

900 1200

600

750

450

Let’s ReviewLet’s Review

Pythagorean Theorem

a2 + b2 = c2

a

b

c

leg2 + leg2 = hypotenuse2

leg

leg hypotenuse

Let’s ReviewA Common Mistakea2 + b2 = c2

Which side is the

hypotenuse?

92 + 122 = 1529 in

15 in12 in

Let’s ReviewCore Lesson

9 in

40 in

41 in 81 + 1600 =

16811681 = 1681

a2 + b2 = c2

Right Triangle

?92 + 402 = 412

?

Let’s ReviewCore Lesson

72 + 142 = 162

49 + 196 = 256

245 < 256

leg2 + leg2 = hypotenuse2

Obtuse Triangle

?

?16 in 14 in

7 in

Let’s ReviewCore Lesson

62 + 122 = 132

36 + 144 = 169

180 > 169

a2 + b2 = c2

Acute Triangle

?

?

12 cm 6 cm

13 cm

In this lesson, you have learned how classify a triangle

by using the Pythagorean Theorem.

Let’s ReviewGuided Practice

7 ft14 ft

16 ft

Classify the triangle below as acute, obtuse or right. Justify your answer.

Let’s ReviewExtension Activities Classify the triangle below as acute, obtuse or right. Justify your answer.

6 in

10 in8 in

Let’s ReviewExtension Activities Classify the triangle below as acute, obtuse or right. Justify your answer.

26 cm

24 cm 12 cm

Let’s ReviewQuick Quiz1) Below are the measurements of a triangle. Using the Pythagorean Theorem, classify the triangle as acute, obtuse, or right.

15, 36, 39

Let’s ReviewQuick Quiz2) Below are the measurements of a triangle. Using the Pythagorean Theorem, classify the triangle as acute, obtuse, or right.

16, 18, 26