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Finding the Fourth Proportional to 421.09, 631.70 and 258.55

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Solution

The fourth proportional to 421.09, 631.70 and 258.55 is: 387.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.09 : 631.70 = 258.55 : x
  2. Step 2: Convert to fraction form
    421.09/631.70 = 258.55/x
  3. Step 3: Cross multiply
    421.09x = 631.70 × 258.55
  4. Step 4: Simplify right side
    421.09x = 163,324.74
  5. Step 5: Solve for x
    x = 163,324.74/421.09
  6. Step 6: Final answer
    x = 387.86

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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.