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Finding the Fourth Proportional to 259.92, 389.95 and 86.63

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Solution

The fourth proportional to 259.92, 389.95 and 86.63 is: 129.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.92 : 389.95 = 86.63 : x
  2. Step 2: Convert to fraction form
    259.92/389.95 = 86.63/x
  3. Step 3: Cross multiply
    259.92x = 389.95 × 86.63
  4. Step 4: Simplify right side
    259.92x = 33,779.20
  5. Step 5: Solve for x
    x = 33,779.20/259.92
  6. Step 6: Final answer
    x = 129.96

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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.