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Finding the Fourth Proportional to 72.20, 108.36 and 54.20

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Solution

The fourth proportional to 72.20, 108.36 and 54.20 is: 81.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.20 : 108.36 = 54.20 : x
  2. Step 2: Convert to fraction form
    72.20/108.36 = 54.20/x
  3. Step 3: Cross multiply
    72.20x = 108.36 × 54.20
  4. Step 4: Simplify right side
    72.20x = 5,873.11
  5. Step 5: Solve for x
    x = 5,873.11/72.20
  6. Step 6: Final answer
    x = 81.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.