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Finding the Fourth Proportional to 391.60, 539.94 and 317.80

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Solution

The fourth proportional to 391.60, 539.94 and 317.80 is: 438.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.60 : 539.94 = 317.80 : x
  2. Step 2: Convert to fraction form
    391.60/539.94 = 317.80/x
  3. Step 3: Cross multiply
    391.60x = 539.94 × 317.80
  4. Step 4: Simplify right side
    391.60x = 171,592.93
  5. Step 5: Solve for x
    x = 171,592.93/391.60
  6. Step 6: Final answer
    x = 438.18

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.