1. 20) 108° 21) 80° 22) 70° 23) 123° 24) 38° 25) 167° 26) 10° 27) 154° 28) 105 = 2x – 11; x = 58 29) 6x + 19 + x = 180; x = 23

2. Ch. 1 Vocab Test is Tuesday!!! Chapter 1 Test is on Wednesday!!!

3. Section 1.7: Introduction to Perimeter, Circumference, and Area

4. Perimeter – The perimeter of a polygon is the sum of the lengths of all its sides. Area – The area of a figure measures the size of the region enclosed by the figure. This is usually expressed in terms of some square unit.

5. A circle is a shape with all points the same distance from its center. A circle is named by its center. Radius – the distance from the center of a circle to any point on the circle. Diameter - the distance across a circle through the center.

6. Square: Side length s P = 4s A = s 2 Rectangle: Length l and width w P = 2l + 2w A = lw

7. Triangle: Side lengths a, b, and c, base b, and height h P = a + b + c A = ½ bh Circle: Radius r Circumference - The distance around a circle. C = 2πr A = πr 2

8. Example 1: Find the perimeter and area of a rectangle of length 4.5 m and width 0.5 m. P = 2l + 2w P = 2(4.5) + 2(0.5) P = 9 + 1 P = 10 m A = lw A = (4.5)(0.5) A = 2.25 m 2

9. Example 2: A road sign consists of a pole with a circular sign on top. The top of the circle is 10 feet high and the bottom of the circle is 8 feet high. Find the diameter, radius, circumference, and area of the circle.

10. 8 ft 10 ft

11. Diameter: 2 ft Radius: 1 ft Circumference: C = 2πr C = 2π(1) C ≈ 6.3 ft Area: A = πr 2 A = π (1) 2 A ≈ 3.1 ft 2

12. Example 3: A rectangle has an area of 36 in. 2 and a length of 9 in. Find its perimeter. A = l ∙ w 36 = 9w 4 = w width = 4 in. Perimeter means to add up all of the sides! P = 26 in.

13. Example 4: A triangle has an area of 48 ft 2 and a base of 16 ft. Find its height. A = ½ bh 48 = ½ (16)(h) 48 = 8h 6 = h height = 6 ft

14. Example 5: A circle has an area of 200π cm 2. Find its radius. A = πr 2 200π = πr 2 200π = πr π 200 = r radius = √200 cm ≈14.1 cm

15. HOMEWORK pg. 55; 9, 12, 15, 16, 17, 20