Nursing Entrance Exam

Nursing Preparation Study Guide

3.5.6 Ratios and Proportions A ratio is a comparison between two different things. For example, a ratio of the number of students who are late to class compared to the number of students who are on time. If 5 students are late and15 students are on time the ratio would be 5:15 or 5 to 15 or > . Ratios can be written in a variety of ways. Proportions are defined as two ratios that are equal to each other. Examples: ~ = Ä or a:b = c:d. When å Å two ratios are equal we can cross multiply the ratios to solve for an unknown value. For example, 3 = 5 35 Cross-multiply and so, 5( ) = 3(35) 5= 105⟹ = 21 Another type of special ratios are unit rates. A unit rate is a ratio (usually different units) expressed as a quantity of one. E.g., a 3 pound bag of sugar costs $3.99, but howmuch are you paying per pound? 3 . = 1 . $3.99 By cross-multiplying and simplifying we get 1 pound of sugar costs $1.33. 3.5.6 Coordinate Plane A coordinate plane is a two-dimensional number line where the vertical line is called the y -axis and the horizontal is called the x -axis. These lines are perpendicular and intersect at their zero points. This point is called the origin. The axes divide the plane into four quadrants. The intersection of the different vertical and horizontal lines creates an ordered pair. The ordered pair is labeled as ( x, y ).The first number corresponds to the x -coordinates and the second to the y -coordinate. To graph an ordered pair on the coordinate plane begin by starting at the origin, (0,0). If the x value is negative, move to the left x units, but if x is positive then you move to the right x units. From there, look at the y value on your coordinate plane. Is y positive? Move up. Is y negative? Move down. To identify the coordinates of an ordered pair that has already been plotted begin at the point itself and follow it down the vertical line. Where does that line cross the x -axis? That is the x component of your ordered pair. Go back to the point and this time trace the horizontal line back to the y -axis. This is the y component of your ordered pair.

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