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Finding the Fourth Proportional to 51.31, 70.76 and 39.65

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Solution

The fourth proportional to 51.31, 70.76 and 39.65 is: 54.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.31 : 70.76 = 39.65 : x
  2. Step 2: Convert to fraction form
    51.31/70.76 = 39.65/x
  3. Step 3: Cross multiply
    51.31x = 70.76 × 39.65
  4. Step 4: Simplify right side
    51.31x = 2,805.91
  5. Step 5: Solve for x
    x = 2,805.91/51.31
  6. Step 6: Final answer
    x = 54.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.