Pythagorean Theorem

Indicator:

G3a: Use Pythagorean Theorem to solve right triangle problems

16

9

25

a

b c

Pythagorean Theorem:a2 + b2 = c2

Given a right triangle with sides a, b, c

Hint: a is shortest side, b is next, c is longest (always across from right angle)

b2

a2

c2

• If a =3in, b=4in find the length of c

a2 + b2 = c2

32 + 42 = c2

9 + 16 = c2

25 = c2

= c (is c Q or I)

5 in = c16

9

c2

+

25

Hint: Think of putting a + sign in the right angle symbol

4in

3in

Determine if the following are right triangles. (Is: a2 + b2 = c2 true)

1) 1.5 mm, 2.5 mm, 2mm

2) 4 ft, 6 ft, 8 ft

?

?

a2 + b2 = c2

1.52 + 22 ? 2.52

2.25 + 4 ? 6.25

Will a 7–foot square mirror fit diagonally through this door way??

3ft

6.5 ft

a2 + b2 = c2

32 + 6.52 = c2

9 + 42.25 = c2

51.25 = c2

= c (is c Q or I)

7.2 c

So, the mirror will fit.

25.51

To find other sides

64.68

4cm9.2 cm

+b

a2 + b2 = c2

42 + b2 = 9.2 2

16 + b2 = 84.64

-16 -16

b2 = 68.64

b =(is b Q or I)

or b 8.3

Assignment

• 11-3/ 482/ 11-30