Pre-Algebra Demystified
ANSWERS 1. 56.7 2. 500 3. 12.5% 4. 5.28 5. 10% Quiz Evaluate5xy when x¼3 and y¼4. (a) 12 (b) 60 (c) 12 (d) 60 Evaluate 3( ...
(b) 11xyþ 10 (c) 2x3yþ 5 (d) 3x5yþ 10 Combine like terms: 5(x3)þ7x8. (a) 2x 5 (b) 12x 23 (c) 12x 11 (d) 3xþ 5 Find the ...
Solve x 7 ¼13. (a) 2 (b) 91 (c) 78 (d) 42 Solve 4xþ 6 ¼34. (a) 10 (b) 10 (c) 7 (d) 7 Solve 3(2x9)¼45. (a) 9 (b) 9 ( ...
60% of what number is 42? Solve using an equation. (a) 70 (b) 25.2 (c) 105 (d) 7 152 CHAPTER 7 Expression and Equations ...
CHAPTER 8 Ratio and Proportion Ratio Aratiois a comparison of two numbers. For example, consider the state- ment, ‘‘About 14 out ...
EXAMPLE If 8 oranges cost $2.00, find the ratio of oranges to cost. SOLUTION 8 oranges 2 dollars ¼ 4 oranges 1 dollar ¼ 4 orange ...
In order to find the unknown in a proportion, cross multiply and then solve the equation for the unknown: i.e., divide by the nu ...
SOLUTION x 15 ¼ 26 75 75x¼ 15 26 Cross multiply 75x¼ 390 75 x 75 ¼ 390 75 Divide by 75 x¼ 515 or 5: 2 PRACTICE Find the value ...
In problems involving proportions, there will always be a ratio statement. It is important to find the ratio statement and then ...
SOLUTION The ratio statement is: 16 yards 3 costumes The proportion is: 16 yards 3 costumes ¼ x yards 8 costumes 16 3 ¼ x 8 16 ...
Solving Percent Problems Using Proportions Recall that percent means part of 100, so a percent can be written as a ratio using 1 ...
SOLUTION 22 % 100 % ¼ 17 : 6 B 22B¼ 17 : 6 100 22B¼ 1760 22 B 22 ¼ 1760 22 B¼ 80 PRACTICE Solve each percent problem by using ...
(a) 7 2 (b) 2 9 (c) 2 7 (d) 7 9 Find the ratio of 6 to 18. (a) 1 : 3 (b) 6 : 24 (c) 18 : 24 (d) 3 : 1 Find the ratio of 12 to 3 ...
(d) 5 2 Find the value of x: 8 9 ¼ x 27 : (a) 16 (b) 12 (c) 8 (d) 24 Find the value of x: 1 3 ¼ 13 x : (a) 39 (b) 3 (c) 13 ( ...
(b) 8^13 (c) 3 (d) 12 On a scale drawing, 3 inches represents 24 feet. How tall is a building that is 5 inches high? (a) 20 fee ...
What percent of 16 is 10? (a) 62.5% (b) 37.5% (c) 12.5% (d) 78.5% Solve using a proportion: 32% of 50 is what number? (a) 8 (b) ...
CHAPTER 9 Informal Geometry Geometric Figures The word ‘‘geometry’’ is derived from two Greek words meaning ‘‘earth measure.’’ T ...
Atriangleis a geometric figure with three sides. Arectangleis a geometric figure with four sides and four 90oangles. The opposit ...
The perimeter of a triangle is found by adding the lengths of the three sides: P¼aþbþc. EXAMPLE Find the perimeter of the triang ...
The perimeter of a square is found by using the formula P¼4s, where s is the length of a side. EXAMPLE Find the perimeter of the ...
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