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Finding the Fourth Proportional to 83.78, 115.54 and 64.11

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Solution

The fourth proportional to 83.78, 115.54 and 64.11 is: 88.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.78 : 115.54 = 64.11 : x
  2. Step 2: Convert to fraction form
    83.78/115.54 = 64.11/x
  3. Step 3: Cross multiply
    83.78x = 115.54 × 64.11
  4. Step 4: Simplify right side
    83.78x = 7,407.27
  5. Step 5: Solve for x
    x = 7,407.27/83.78
  6. Step 6: Final answer
    x = 88.41

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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.