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Finding the Fourth Proportional to 485.60, 728.04 and 280.40

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Solution

The fourth proportional to 485.60, 728.04 and 280.40 is: 420.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.60 : 728.04 = 280.40 : x
  2. Step 2: Convert to fraction form
    485.60/728.04 = 280.40/x
  3. Step 3: Cross multiply
    485.60x = 728.04 × 280.40
  4. Step 4: Simplify right side
    485.60x = 204,142.42
  5. Step 5: Solve for x
    x = 204,142.42/485.60
  6. Step 6: Final answer
    x = 420.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.