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Finding the Fourth Proportional to 74.75, 102.78 and 72.47

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Solution

The fourth proportional to 74.75, 102.78 and 72.47 is: 99.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.75 : 102.78 = 72.47 : x
  2. Step 2: Convert to fraction form
    74.75/102.78 = 72.47/x
  3. Step 3: Cross multiply
    74.75x = 102.78 × 72.47
  4. Step 4: Simplify right side
    74.75x = 7,447.95
  5. Step 5: Solve for x
    x = 7,447.95/74.75
  6. Step 6: Final answer
    x = 99.64

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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.