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. . NOISIAICI NVOlUäWV IOOHOS S170d017äH 1001. Mr. Mohamed Fawzy.

. . Variation. .

. . A) Directly proportional ( y = k x ). Ex1: If y is directly prop. To x and y = 15 when x = 5. Find y when x = 25?.

. . Ex2:. y = k x. 14 = k 42. . K =. 14 42 =. 1 3.

. . Ex3:. y = k x. 40 = k 14. . K =. 40 14 =. 20 7.

. . Ex4:. km hr 150 6 ? 10. y =. 150×10. 6 = 250.

. . Ex5:. W R 14 84 ? 144. y =. 14×144. 84 = 24. .

. . B) Inversely proportional: (y =. ? ? ). Ex1: If y is inversely prop. To x and y= 15 when x = 5. What is the value of y when x = 25?.

. . Ex2: If y is inversely prop. To x and y= 50 when x = 5. What is the value of y when x = 10?.

. . Ex3:. y =. 6 1.5. y =. 3×2 1.5 = 4. y = 4. . .

. . Ex4:. y =. 8 16. y =. 2×4 16 =. 1 2. y =. 1 2.

. . Ex1: If y = k x, where k is a constant and y = 24 when x = 6, what is the value of y when x = 5? A) 6 B) 15 C) 20 D) 23 Ex2: If y inversely proportional to x and y = 15 when x = 5, what is the value of y when x = 25 A).

. . Ex3: The force required to stretch a spring beyond its natural length is proportional to how far the spring is being stretched. If a force of 15 pounds stretches a spring 8 centimeters beyond its natural length, what force in pounds is needed to stretch this spring 20 centimeters beyond its natural length? A) 27 B) 30.5 C) 35 D) 37.5.

. . Ex4: Which of the following tables shows a relationship in which w is directly proportional to x ?.

. . Ex5: Which of the following tables shows a relationship in which w is inversely proportional to x ?.