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Finding the Fourth Proportional to 420.57, 631.05 and 258.15

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Solution

The fourth proportional to 420.57, 631.05 and 258.15 is: 387.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.57 : 631.05 = 258.15 : x
  2. Step 2: Convert to fraction form
    420.57/631.05 = 258.15/x
  3. Step 3: Cross multiply
    420.57x = 631.05 × 258.15
  4. Step 4: Simplify right side
    420.57x = 162,905.56
  5. Step 5: Solve for x
    x = 162,905.56/420.57
  6. Step 6: Final answer
    x = 387.34

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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.