146 Chapter 2 Linear Equations and Inequalities in One Variable Student Check 6 Find the measure of each angle in the triangle. a. A 4a 5 4a – 5 a B C b. In a triangle ABC, the measure of angle A is twice the measure of angle C. The measure of angle B is 20° less than the measure of angle C. Find the measure of each angle. Troubleshooting Common Errors Some common errors associated with formulas and geometry applications are illustrated next. Objective 7 Examples A problem and an incorrect solution are given. Provide the correct solution and an explanation of the error. 7a. Solve d = rt for t. Incorrect Solution Correct Solution and Explanation The variable r is connected to t by multiplication. Therefore, we must divide both sides by r to isolate t. d = rt d r = rt r d r = t 7b. The complement of an angle is six degrees less than seven times the measure of the angle. Find the measure of the angle. Incorrect Solution Correct Solution and Explanation The error was made in representing the complement of the angle. If a is the measure of the angle, then 90 - a is the measure of the complement. Also, it is unreasonable to have a negative value for the measure of an angle. 90 - a = 7a - 6 96 = 8a 96 8 = 8a 8 12 = a The angle is 12°. Objective 7 ▶ Troubleshoot common errors. d = rt d - r = t Let a be the measure of the angle.Then a - 90 is the a - = 7a - 6 -84 6a -84 6 = 6 -14 = a The angle 14°. t gle. T measure of the complement. 90 = 6a ngle is 14 ANSWERS TO STUDENT CHECKS Student Check 1 a. $150 b. F = 122° c. 651 mi Student Check 2 a. The length of the painting is 390 in. Its area is 102,180 in.2. b. The base of the triangle is 5 ft. c. The dimensions of the White House are 168 ft by 85.5 ft. d. The circumference of the clock is 72.3 ft. The area is 415.5 ft2.
hendricks_beginning_intermediate_algebra_1e_ch1_3
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