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Finding the Fourth Proportional to 77.40, 115.86 and 57.06

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Solution

The fourth proportional to 77.40, 115.86 and 57.06 is: 85.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.40 : 115.86 = 57.06 : x
  2. Step 2: Convert to fraction form
    77.40/115.86 = 57.06/x
  3. Step 3: Cross multiply
    77.40x = 115.86 × 57.06
  4. Step 4: Simplify right side
    77.40x = 6,610.97
  5. Step 5: Solve for x
    x = 6,610.97/77.40
  6. Step 6: Final answer
    x = 85.41

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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.