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Finding the Fourth Proportional to 31.65, 47.20 and 26.78

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Solution

The fourth proportional to 31.65, 47.20 and 26.78 is: 39.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.65 : 47.20 = 26.78 : x
  2. Step 2: Convert to fraction form
    31.65/47.20 = 26.78/x
  3. Step 3: Cross multiply
    31.65x = 47.20 × 26.78
  4. Step 4: Simplify right side
    31.65x = 1,264.02
  5. Step 5: Solve for x
    x = 1,264.02/31.65
  6. Step 6: Final answer
    x = 39.94

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.