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Finding the Fourth Proportional to 77.31, 115.74 and 51.57

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Solution

The fourth proportional to 77.31, 115.74 and 51.57 is: 77.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.31 : 115.74 = 51.57 : x
  2. Step 2: Convert to fraction form
    77.31/115.74 = 51.57/x
  3. Step 3: Cross multiply
    77.31x = 115.74 × 51.57
  4. Step 4: Simplify right side
    77.31x = 5,968.71
  5. Step 5: Solve for x
    x = 5,968.71/77.31
  6. Step 6: Final answer
    x = 77.20

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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.