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Finding the Fourth Proportional to 81.90, 113.04 and 52.80

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Solution

The fourth proportional to 81.90, 113.04 and 52.80 is: 72.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.90 : 113.04 = 52.80 : x
  2. Step 2: Convert to fraction form
    81.90/113.04 = 52.80/x
  3. Step 3: Cross multiply
    81.90x = 113.04 × 52.80
  4. Step 4: Simplify right side
    81.90x = 5,968.51
  5. Step 5: Solve for x
    x = 5,968.51/81.90
  6. Step 6: Final answer
    x = 72.88

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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.