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Finding the Fourth Proportional to 53.86, 80.72 and 42.40

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Solution

The fourth proportional to 53.86, 80.72 and 42.40 is: 63.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    53.86 : 80.72 = 42.40 : x
  2. Step 2: Convert to fraction form
    53.86/80.72 = 42.40/x
  3. Step 3: Cross multiply
    53.86x = 80.72 × 42.40
  4. Step 4: Simplify right side
    53.86x = 3,422.53
  5. Step 5: Solve for x
    x = 3,422.53/53.86
  6. Step 6: Final answer
    x = 63.54

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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.