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Finding the Fourth Proportional to 485.40, 727.92 and 280.08

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Solution

The fourth proportional to 485.40, 727.92 and 280.08 is: 420.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.40 : 727.92 = 280.08 : x
  2. Step 2: Convert to fraction form
    485.40/727.92 = 280.08/x
  3. Step 3: Cross multiply
    485.40x = 727.92 × 280.08
  4. Step 4: Simplify right side
    485.40x = 203,875.83
  5. Step 5: Solve for x
    x = 203,875.83/485.40
  6. Step 6: Final answer
    x = 420.02

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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.