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Finding the Fourth Proportional to 71.66, 98.78 and 55.20

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Solution

The fourth proportional to 71.66, 98.78 and 55.20 is: 76.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.66 : 98.78 = 55.20 : x
  2. Step 2: Convert to fraction form
    71.66/98.78 = 55.20/x
  3. Step 3: Cross multiply
    71.66x = 98.78 × 55.20
  4. Step 4: Simplify right side
    71.66x = 5,452.66
  5. Step 5: Solve for x
    x = 5,452.66/71.66
  6. Step 6: Final answer
    x = 76.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.