Pythagorean Theorem

5-18-09IMP3Sia

Today’s AgendaBell RingerHand back HW16 and quizzesPythagorean Theorem reviewHW4 p. 75 due Friday, May 22nd

AnnouncementsIf you missed last week’s quiz, you have until this

Friday, 5-22-09 to make them up!HW Hall this Tuesday and Thursday during 9th periodACT session Friday, May 30th in room 208 from 8am-

10am# of students who completed HW16

3rd period: 13 out of 24 (54%) 4th period: 8 out of 17 (47%) 5th period: 8 out of 18 (44%)

Current grades: 3rd period: 3 A’s, 9 F’s 4th period: 2 A’s, 3 F’s 5th period: 3 A’s, 7 F’s

HW16 p. 1051. 250,000/300 boxes2. 200 meters3. No, a 30 feet board won’t be long enough

because the diameter of the pond is about 31.83 feet.

4. The banner should be about 60.03 feet long.

What we’ve done so far…THE BASICS: lines,

rays, segments, points, angles, triangles

CIRCLES: radius, diameter, area, circumference,

This week…RIGHT

TRIANGLES: right angles, legs, hypotenuse, Pythagorean Theorem, special angles

Pythagorean TheoremThe Pythagorean Theorem helps you find

missing sides of right triangles.PT is used in:

PhysicsConstructionPlumbingEngineeringArchitecture

Right TrianglesPythagorean Theorem only applies to right

triangles.You must be able to first identify parts of a

right triangle to correctly use Pythagorean Theorem.

Pythagorean Theorem The theorem states

that the squares of the lengths of the sides of the triangle are equal to the square of the hypotenuse.

The legs are a and b (it doesn’t matter which leg is a or b).

The hypotenuse is ALWAYS c.

Using the Pythagorean Theorem There is a building with a 12 ft high

window. You want to use a ladder to go up to the window, and you decide to keep the ladder 5 ft away from the building to have a good slant. How long should the ladder be?

1. Draw a picture and label a, b, and c.2. Write the Pythagorean Theorem. a2 + b2

= c2

3. Plug in a, b, and c. 52 + 122 = c2

4. Solve for the missing variable. 5. Check that you’ve solved for the missing

variable, NOT THE MISSING VARIABLE SQUARED.

ca

b

Try this on your own…On a baseball diamond the bases are 90 ft

apart. What is the distance from home plate to second base in a straight line?

Follow the steps you just wrote down.

a2 + b2 = c2

902 + 902 = c2

8100 + 8100 = 16200 = c2

127.28 = c