Tham khảo tài liệu 'university math english 1', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ---------------------------------- ACT MATH TEST PRACTICE --------------------------------------------- 55. Choice e is correct. Three of the answer choices can be immediately eliminated because the length of the height cannot be negative. Answer choices b c and d all have negative lengths. Call the height h and the base h 5. The area of a triangle is -y-. Substitute in h and h 5 for the base and height and set the area equal to 80 since the are of the given triangle is 80 h h2 5 80 Solve for h. The equation is quadratic so the quadratic formula will be used h 5h 80 h2 5h 160 h2 5h - 160 h Use the quadratic formula to solve. -5 V 5 2 - 4 1 -160 2 1 -5 V25 640 2 -5 V665 2 The negative value is eliminated from the answer because it does not make sense. The answer is -5 V665 . 2 56. Choice i is correct. The easiest way to find the length of one side is to draw the square on the coordinate plane and count the spaces. There are 7 spaces between -2 3 and 5 3 . Therefore the length of a side is 7. -2 3 . 7 . 5 3 -------1---1 I I I j o-------------ị -2 -4 5 -4 The distance formula can also be used. First you must decide which points are consecutive vertices of the square. Let s use -2 3 and 5 3 . The distance formula is then d V 5 - -2 2 3 - 3 2 d V72 0 d V49 d 7 194 --------------------------------- ACT MATH TEST PRACTICE --------------------------------------------- 57. Choice e is correct. The slope of the given equation is 3. The slope of a line perpendicular to the line is the opposite reciprocal of 3. This is -y. Arrange each answer choice in the y mx b format to quickly find the slope of each choice. a. y 3x 2 b. y 3x - 4 21 c. y 9X 3 d. y -2x 4 e. y - Jx J 58. Choice f is correct. Arrange the equations of the two lines in y mx b format. They both become y -jx 4. Therefore they are the same line. 59. Choice b is correct. To find the midpoint take the average of the x values and the average of the y values. -4 3 2 8 -Í f 3 The midpoint is 3 . 60. Choice i .
