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Finding the Fourth Proportional to 77.00, 115.20 and 66.15

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Solution

The fourth proportional to 77.00, 115.20 and 66.15 is: 98.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.00 : 115.20 = 66.15 : x
  2. Step 2: Convert to fraction form
    77.00/115.20 = 66.15/x
  3. Step 3: Cross multiply
    77.00x = 115.20 × 66.15
  4. Step 4: Simplify right side
    77.00x = 7,620.48
  5. Step 5: Solve for x
    x = 7,620.48/77.00
  6. Step 6: Final answer
    x = 98.97

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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.