January 20 and January 21 Perimeters and Areas Why? Because they will be used to find surface areas and volumes For a fresh start for 2nd semester, everyone glue a tab to page 68 and write Semester 2 on that page. Start notes on page 70.

Check your assignment; Turn it in by passing it forward.

AB means the length of or the distance between points A and B Check the list of symbols in the front of your notebook. You should have the following symbols: A means point A means the line segment with endpoints at A and B means the line that goes through points A and B means the ray that starts at A and goes through B AB means the length of or the distance between points A and B means an angle with vertex at B, one side is a ray that goes through point A and the other side is a ray that goes through point B m means the measure of the angle with vertex B. This is usually given in degrees.

means congruent to means similar to means triangle with vertices point A, point B and point C means parallel to means perpendicular to means translate <x, y> is the vector that tells how far to translate, and in which direction or means reflect across the line m or means rotate around the given point the given number of degrees. Positive rotation is counterclockwise.

Turn to page 70 in your notebook. Perimeter: the distance around the outside of a two dimensional figure (a polygon). Find the sum of the sides. P = 6cm + 7 cm + 8 cm + 4 cm = 25 cm

For each of these: P = b + h + b + h or P = 2b + 2h or P = 2(b+h) Instead of calling the sides of a rectangle the length and the width, we will now call he sides the base and the height. Since a rectangle is a parallelogram the opposite sides are congruent, meaning they have the same measure. For each of these: P = b + h + b + h or P = 2b + 2h or P = 2(b+h) You can use any of these formulas.

Area: The amount of space inside the boundary of a two dimensional (or flat) figure. Area is measured in square units, such as square inches or square meters, or square miles. For a rectangle multiply the base times the height. For all of these A = bh

Calculate the area of each of the figures. A = (7.3cm)(2.9cm) = 21.2 sq cm A = (2.4 cm)(5 cm) = 12 sq cm A = (2.6cm)(4.2cm) = 26 sq cm Why would each of the answers shown here have only one decimal place?

Work on the paper that has Activity 21 on one side and Activity 22 on the other. It is due next class.