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Finding the Fourth Proportional to 72.89, 100.60 and 61.21

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Solution

The fourth proportional to 72.89, 100.60 and 61.21 is: 84.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.89 : 100.60 = 61.21 : x
  2. Step 2: Convert to fraction form
    72.89/100.60 = 61.21/x
  3. Step 3: Cross multiply
    72.89x = 100.60 × 61.21
  4. Step 4: Simplify right side
    72.89x = 6,157.70
  5. Step 5: Solve for x
    x = 6,157.70/72.89
  6. Step 6: Final answer
    x = 84.48

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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.