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Finding the Fourth Proportional to 420.85, 580.59 and 287.92

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Solution

The fourth proportional to 420.85, 580.59 and 287.92 is: 397.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.85 : 580.59 = 287.92 : x
  2. Step 2: Convert to fraction form
    420.85/580.59 = 287.92/x
  3. Step 3: Cross multiply
    420.85x = 580.59 × 287.92
  4. Step 4: Simplify right side
    420.85x = 167,163.47
  5. Step 5: Solve for x
    x = 167,163.47/420.85
  6. Step 6: Final answer
    x = 397.20

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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.