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Finding the Fourth Proportional to 421.12, 630.60 and 258.31

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Solution

The fourth proportional to 421.12, 630.60 and 258.31 is: 386.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.12 : 630.60 = 258.31 : x
  2. Step 2: Convert to fraction form
    421.12/630.60 = 258.31/x
  3. Step 3: Cross multiply
    421.12x = 630.60 × 258.31
  4. Step 4: Simplify right side
    421.12x = 162,890.29
  5. Step 5: Solve for x
    x = 162,890.29/421.12
  6. Step 6: Final answer
    x = 386.80

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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.