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Finding the Fourth Proportional to 54.90, 81.90 and 51.48

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Solution

The fourth proportional to 54.90, 81.90 and 51.48 is: 76.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.90 : 81.90 = 51.48 : x
  2. Step 2: Convert to fraction form
    54.90/81.90 = 51.48/x
  3. Step 3: Cross multiply
    54.90x = 81.90 × 51.48
  4. Step 4: Simplify right side
    54.90x = 4,216.21
  5. Step 5: Solve for x
    x = 4,216.21/54.90
  6. Step 6: Final answer
    x = 76.80

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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.