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Finding the Fourth Proportional to 28.20, 42.60 and 26.40

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Solution

The fourth proportional to 28.20, 42.60 and 26.40 is: 39.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.20 : 42.60 = 26.40 : x
  2. Step 2: Convert to fraction form
    28.20/42.60 = 26.40/x
  3. Step 3: Cross multiply
    28.20x = 42.60 × 26.40
  4. Step 4: Simplify right side
    28.20x = 1,124.64
  5. Step 5: Solve for x
    x = 1,124.64/28.20
  6. Step 6: Final answer
    x = 39.88

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.