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Finding the Fourth Proportional to 261.32, 391.70 and 87.83

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Solution

The fourth proportional to 261.32, 391.70 and 87.83 is: 131.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.32 : 391.70 = 87.83 : x
  2. Step 2: Convert to fraction form
    261.32/391.70 = 87.83/x
  3. Step 3: Cross multiply
    261.32x = 391.70 × 87.83
  4. Step 4: Simplify right side
    261.32x = 34,400.61
  5. Step 5: Solve for x
    x = 34,400.61/261.32
  6. Step 6: Final answer
    x = 131.64

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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.