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Finding the Fourth Proportional to 402.12, 555.30 and 285.75

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Solution

The fourth proportional to 402.12, 555.30 and 285.75 is: 394.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.12 : 555.30 = 285.75 : x
  2. Step 2: Convert to fraction form
    402.12/555.30 = 285.75/x
  3. Step 3: Cross multiply
    402.12x = 555.30 × 285.75
  4. Step 4: Simplify right side
    402.12x = 158,676.98
  5. Step 5: Solve for x
    x = 158,676.98/402.12
  6. Step 6: Final answer
    x = 394.60

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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.