EXAMPLE 5 Find the missing angle measures. (5x 1 7)8 478 x8 B A C Solution Step 1: Read the problem carefully, and identify what we are being asked to fi nd. Find the missing angle measures. Step 2: The unknowns are already defi ned. We must fi nd x, the measure of one angle, and then 5x 7, the measure of the other angle. Step 3: Translate the information into an algebraic equation. Since the sum of the angles in a triangle is 180, we can write English: Measure of Measure of Measure of one angle plus second angle plus third angle is 180 T T T T T T T Equation: x 47 5x 7 180 The equation is x 47 (5x 7) 180. Step 4: Solve the equation. x 47 (5x 7) 180 6x 54 180 Combine like terms. 6x 54 54 180 54 Subtract 54 from each side. 6x 126 Combine like terms. 6x 6 126 6 Divide each side by 6. x 21 Simplify. Step 5: Check the answer and interpret the solution as it relates to the problem. One angle, x, has a measure of 21. The other unknown angle measure is 5x 7 5(21) 7 112. The answer makes sense because the sum of the angle measures is 21 47 112 180. YOU TRY 5 Find the missing angle measures. 608 (2x 1 3)8 x8 A B C ANSWERS TO YOU TRY EXERCISES 1) 8 ft 2) 14 m 3) 16 ft 4) 4 ft by 5 ft 5) mA 39; mB 81 www.mhhe.com/messersmith SECTION 4.5 Solving Geometry Applications Using Algebra 337
messersmith_power_prealgebra_1e_ch4_7_10
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