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Finding the Fourth Proportional to 102.78, 141.91 and 66

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Solution

The fourth proportional to 102.78, 141.91 and 66 is: 91.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.78 : 141.91 = 66 : x
  2. Step 2: Convert to fraction form
    102.78/141.91 = 66/x
  3. Step 3: Cross multiply
    102.78x = 141.91 × 66
  4. Step 4: Simplify right side
    102.78x = 9,366.06
  5. Step 5: Solve for x
    x = 9,366.06/102.78
  6. Step 6: Final answer
    x = 91.13

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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.