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Finding the Fourth Proportional to 51.91, 77.79 and 31.57

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Solution

The fourth proportional to 51.91, 77.79 and 31.57 is: 47.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.91 : 77.79 = 31.57 : x
  2. Step 2: Convert to fraction form
    51.91/77.79 = 31.57/x
  3. Step 3: Cross multiply
    51.91x = 77.79 × 31.57
  4. Step 4: Simplify right side
    51.91x = 2,455.83
  5. Step 5: Solve for x
    x = 2,455.83/51.91
  6. Step 6: Final answer
    x = 47.31

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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.