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Finding the Fourth Proportional to 499.60, 687.72 and 389.20

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Solution

The fourth proportional to 499.60, 687.72 and 389.20 is: 535.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.60 : 687.72 = 389.20 : x
  2. Step 2: Convert to fraction form
    499.60/687.72 = 389.20/x
  3. Step 3: Cross multiply
    499.60x = 687.72 × 389.20
  4. Step 4: Simplify right side
    499.60x = 267,660.62
  5. Step 5: Solve for x
    x = 267,660.62/499.60
  6. Step 6: Final answer
    x = 535.75

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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.