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Finding the Fourth Proportional to 247.79, 371.59 and 85.42

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Solution

The fourth proportional to 247.79, 371.59 and 85.42 is: 128.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    247.79 : 371.59 = 85.42 : x
  2. Step 2: Convert to fraction form
    247.79/371.59 = 85.42/x
  3. Step 3: Cross multiply
    247.79x = 371.59 × 85.42
  4. Step 4: Simplify right side
    247.79x = 31,741.47
  5. Step 5: Solve for x
    x = 31,741.47/247.79
  6. Step 6: Final answer
    x = 128.10

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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.