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Finding the Fourth Proportional to 72.78, 108.56 and 66.70

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Solution

The fourth proportional to 72.78, 108.56 and 66.70 is: 99.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.78 : 108.56 = 66.70 : x
  2. Step 2: Convert to fraction form
    72.78/108.56 = 66.70/x
  3. Step 3: Cross multiply
    72.78x = 108.56 × 66.70
  4. Step 4: Simplify right side
    72.78x = 7,240.95
  5. Step 5: Solve for x
    x = 7,240.95/72.78
  6. Step 6: Final answer
    x = 99.49

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.