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Finding the Fourth Proportional to 259.51, 389.19 and 86.15

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Solution

The fourth proportional to 259.51, 389.19 and 86.15 is: 129.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.51 : 389.19 = 86.15 : x
  2. Step 2: Convert to fraction form
    259.51/389.19 = 86.15/x
  3. Step 3: Cross multiply
    259.51x = 389.19 × 86.15
  4. Step 4: Simplify right side
    259.51x = 33,528.72
  5. Step 5: Solve for x
    x = 33,528.72/259.51
  6. Step 6: Final answer
    x = 129.20

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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.