Geometry Review. Here are some formulas and concepts that you will need to review before working on the practice exam.

Transcription

1 Geometry Review Here are some formulas and concepts that you will need to review before working on the practice eam. Triangles o Perimeter or the distance around the triangle is found by adding all of the sides, or, P = a + b + c, where P is the perimeter and a, b, and c are the sides of the triangle. a c b o rea is found by taking half of the product of the base and the height. Or, 1 bh, where is the area, b is the base and h is the height. Notice 2 that the height always forms a right angle with the base and, in some cases the height may lie outside the triangle. h h b b o The sum of the three angles of any triangle is always o Pythagorean Theorem states that for any right triangle, a b c, where c is the hypotenuse, and a and b are the other two sides of the right triangle. c a b Rectangles o Perimeter or the distance around the rectangle is found by adding all the sides or by using P 2L 2W where P is the perimeter, L is the length and W is the width. o rea is given by the width. L W, where is the area, L is the length and W is W L Revised on 11/2/2009 Page 1 of 10

2 Squares o Perimeter or the distance around the square is found by multiplying a side by 4, or, P = 4a, where P is the perimeter and a is the length of a side. o rea is found by squaring a side, or, the length of a side. a 2 a, where is the area and a is ircles o ircumference or the distance around the circle is found by using 2 r, or d, where is the circumference, r is the radius, d is the diameter and can be approimated as o rea is given by 2 r, where is the area, r is the radius, and is approimated as o If instead of the radius r, the diameter d is given, divide d by 2 to find the radius. In other words, r = d / 2. r d r Similar Triangles o Two triangles are similar if they have the same shape, but one is just a reduction or enlargement of the other (like on a copy machine). D E F o DEF means that triangles and DEF above are similar. In similar triangles the ratios of corresponding sides are equal and the corresponding angles are equal. Therefore for the above triangles we have: DE DF EF and D, E, F. Revised on 11/2/2009 Page 2 of 10

3 Parallel Lines For the parallel lines L 1 and L 2, all the given pairs of angles are congruent L L 2 o lternate Interior ngles: 4 and 6 3 and 5 o orresponding ngles: 1 and 5 2 and 6 3 and 7 4 and 8 o lternate Eterior ngles: 1 and 7 2 and 8 o Vertical ngles: 1 and 3 2 and 4 6 and 8 5 and 7 ngles o flat angle is o square (right) angle is Key for the Sample Problems The sample problems start on the net page D D D D D D D Revised on 11/2/2009 Page 3 of 10

4 Geometry Sample Problems You will find the answers on the bottom of page 3 of this packet. 1. Find the perimeter of the rectangle. 6 ft 8 ft 9 in. 177 in. 29 ft 6 in ft D ft 2. Find the perimeter of the rectangle. 6 ft 9 ft 9 in ft. 200 in ft D. 31 ft 6 in 3. Find the perimeter of the rectangle. 3 ft 7 ft 6 in. 10 ft 6 in. 126 in. 21 ft D ft 4. Find the measure of angle D Find the measure of angle D. 157 Revised on 11/2/2009 Page 4 of 10

5 6. Find the measure of angle D The perimeter of the triangle is 145 inches. Find the length inches. 145 inches. 56 inches D. 61 inches The perimeter of the triangle is 135 meters. Find the length meters. 26 meters. 52 meters D. 135 meters The perimeter of the triangle is 122 feet. Find the length ft. 25 ft. 50 ft D. 100 ft The perimeter of a square is 60 inches. Find the area sq in. 225 sq in. 900 sq in D sq in Revised on 11/2/2009 Page 5 of 10

6 11. The perimeter of a square is 100 centimeters. Find the area sq cm. 10,000 sq cm sq cm D sq cm 12. The perimeter of a square is 40 meters. Find the area sq m sq m sq m D sq m 13. Lines L 1 and L 2 are parallel. Find the measure of. 63 L D. 117 L Lines L 1 and L 2 are parallel. Find the measure of y. L D y L Lines L 1 and L 2 are parallel. Find the measure of. 77 L D. 157 L 2 Revised on 11/2/2009 Page 6 of 10

7 16. Find the area of the figure. 10 in 15 in 15 in 20 in. 800 sq in. 650 sq in. 500 sq in D. 575 sq in 40 in 17. Find the area of the figure. 15 m 15 m 5 m. 800 sq m. 900 sq m. 805 sq m D. 875 sq m 30 m 40 m 18. Find the area of the figure. 20 in 15 in 10 in 5 in. 600 sq in. 550 sq in. 525 sq in D. 575 sq in 30 in 19. Find the length of the diagonal of the rectangle based on the given information. 5 in. 19 in. 17 in. 15 in D. 13 in 12 in Revised on 11/2/2009 Page 7 of 10

8 20. Find the length of the diagonal of the rectangle based on the given information. 9 ft. 15 ft. 18 ft. 21 ft D. 16 ft 12 ft 21. Find the length of the diagonal of the rectangle based on the given information. 6 m. 10 in. 17 in. 15 in D. 13 in 8 m 22. The two triangles are similar. Find the length of DE. E ½ D. 10 ½ D F The two triangles are similar. Find the length of DE. 3 5 D ½ D. 4 ½ 4 E 6 F Revised on 11/2/2009 Page 8 of 10

9 24. The two triangles are similar. Find the length of EF. 6 D ½. 9 D. 12 ½ E F 25. The diameter of a circle is 10 inches. What is its circumference?. between 15 and 16 inches. between 31 and 32 inches. between 47 and 48 inches D. between 28 and 29 inches 26. The diameter of a circle is 1 centimeter. What is its circumference?. between 1 and 2 cm. between 2 and 3 cm. between 3 and 4 cm D. between 4 and 5 cm 27. The radius of a circle is 5 inches. What is its circumference?. between 15 and 16 inches. between 31 and 32 inches. between 47 and 48 inches D. between 28 and 29 inches 28. Find the area of the triangle. 3.5 in. 7 sq in. 14 sq in. 28 sq in D. an t be done 4 in Revised on 11/2/2009 Page 9 of 10

10 29. Find the area of the triangle. 4.5 m sq m sq m. 27 sq m D. an t be done 6 m 30. Find the area of the triangle. 5 in 3 in. 12 sq in. 15 sq in. 6 sq in D. 10 sq in 4 in Revised on 11/2/2009 Page 10 of 10