Take the WOOName: Section:

Date: Number:

Pythagorean Theorem

Part I: NotesThe Pythagorean Theorem lets us solve for sides of a triangle that

we don’t know.

c

a

b

Part II: How to Use

When you are solving problems involving right triangles, remember the acronym

DSSIS for the 5 steps of the solution process. This stands for:

1. Draw a picture

2.

3. Simplify

4.

5. Square root

Problem 1: A 20 foot ladder is leaned against a wall. If the base of the ladder is 8 feet from the wall, how high up the wall will the ladder reach.

STEP 1 DRAW A PICTURE

STEP 2 SUBSTITUTE THE KNOWN SIDES

STEP 3 SIMPLIFY

STEP 4 ISOLATE THE VARIABLE

Take the WOOName: Section:

Date: Number:

STEP 5 SQUARE ROOT

Problem 2: Two friends walk away from each other at a 90 degree angle. They both walk 12 feet away, then they stop. When they stop, how far apart are they?

STEP 1 DRAW A PICTURE

STEP 2 SUBSTITUTE THE KNOWN SIDES

STEP 3 SIMPLIFY

STEP 4 ISOLATE THE VARIABLE

STEP 5 SQUARE ROOT

Problem 3: A tree that is 8 feet tall casts a 6 foot shadow. A ladder is placed at the end of the shadow to the top of the tree. What is the length of the ladder?

STEP 1 DRAW A PICTURE

STEP 2 SUBSTITUTE THE KNOWN SIDES

STEP 3 SIMPLIFY

STEP 4 ISOLATE THE VARIABLE

Take the WOOName: Section:

Date: Number:

STEP 5 SQUARE ROOT

Part III: Your Turn

Directions: Solve the following problems using the Pythagorean Theorem. Refer to the steps we just went over to help you solve them.

1. One leg of a right triangle is 10 inches. The other leg is 12 inches. What is the length of the hypotenuse?

2. One leg of a right triangle is 3.54 meters. The hypotenuse is 5 meters. What is the length of the other leg?

3. Firefighters have a 17-foot extension ladder. In order to reach 15 feet up a building, how far away from the building should the foot of the ladder be placed?

4. George rides his bike in one direction for 9 miles. Then takes a 90 degree turn and bikes for 12 miles. How far is he from his starting point?

5. Donna's TV screen is 20 inches tall. If the diagonal measures 25 inches, what is the width of Donna's TV?