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Finding the Fourth Proportional to 70.78, 97.62 and 55.21

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Solution

The fourth proportional to 70.78, 97.62 and 55.21 is: 76.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.78 : 97.62 = 55.21 : x
  2. Step 2: Convert to fraction form
    70.78/97.62 = 55.21/x
  3. Step 3: Cross multiply
    70.78x = 97.62 × 55.21
  4. Step 4: Simplify right side
    70.78x = 5,389.60
  5. Step 5: Solve for x
    x = 5,389.60/70.78
  6. Step 6: Final answer
    x = 76.15

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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.