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Finding the Fourth Proportional to 81.00, 121.45 and 52.10

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Solution

The fourth proportional to 81.00, 121.45 and 52.10 is: 78.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.00 : 121.45 = 52.10 : x
  2. Step 2: Convert to fraction form
    81.00/121.45 = 52.10/x
  3. Step 3: Cross multiply
    81.00x = 121.45 × 52.10
  4. Step 4: Simplify right side
    81.00x = 6,327.55
  5. Step 5: Solve for x
    x = 6,327.55/81.00
  6. Step 6: Final answer
    x = 78.12

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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.