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Finding the Fourth Proportional to 259.70, 389.60 and 86.37

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Solution

The fourth proportional to 259.70, 389.60 and 86.37 is: 129.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.70 : 389.60 = 86.37 : x
  2. Step 2: Convert to fraction form
    259.70/389.60 = 86.37/x
  3. Step 3: Cross multiply
    259.70x = 389.60 × 86.37
  4. Step 4: Simplify right side
    259.70x = 33,649.32
  5. Step 5: Solve for x
    x = 33,649.32/259.70
  6. Step 6: Final answer
    x = 129.57

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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.