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Finding the Fourth Proportional to 430.86, 646.10 and 138.31

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Solution

The fourth proportional to 430.86, 646.10 and 138.31 is: 207.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.86 : 646.10 = 138.31 : x
  2. Step 2: Convert to fraction form
    430.86/646.10 = 138.31/x
  3. Step 3: Cross multiply
    430.86x = 646.10 × 138.31
  4. Step 4: Simplify right side
    430.86x = 89,360.30
  5. Step 5: Solve for x
    x = 89,360.30/430.86
  6. Step 6: Final answer
    x = 207.40

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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.