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Finding the Fourth Proportional to 259.72, 389.49 and 86.35

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Solution

The fourth proportional to 259.72, 389.49 and 86.35 is: 129.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.72 : 389.49 = 86.35 : x
  2. Step 2: Convert to fraction form
    259.72/389.49 = 86.35/x
  3. Step 3: Cross multiply
    259.72x = 389.49 × 86.35
  4. Step 4: Simplify right side
    259.72x = 33,632.46
  5. Step 5: Solve for x
    x = 33,632.46/259.72
  6. Step 6: Final answer
    x = 129.50

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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.