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Finding the Fourth Proportional to 40.45, 55.78 and 28.79

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Solution

The fourth proportional to 40.45, 55.78 and 28.79 is: 39.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.45 : 55.78 = 28.79 : x
  2. Step 2: Convert to fraction form
    40.45/55.78 = 28.79/x
  3. Step 3: Cross multiply
    40.45x = 55.78 × 28.79
  4. Step 4: Simplify right side
    40.45x = 1,605.91
  5. Step 5: Solve for x
    x = 1,605.91/40.45
  6. Step 6: Final answer
    x = 39.70

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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.