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Finding the Fourth Proportional to 259.12, 388.51 and 85.71

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Solution

The fourth proportional to 259.12, 388.51 and 85.71 is: 128.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.12 : 388.51 = 85.71 : x
  2. Step 2: Convert to fraction form
    259.12/388.51 = 85.71/x
  3. Step 3: Cross multiply
    259.12x = 388.51 × 85.71
  4. Step 4: Simplify right side
    259.12x = 33,299.19
  5. Step 5: Solve for x
    x = 33,299.19/259.12
  6. Step 6: Final answer
    x = 128.51

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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.