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Finding the Fourth Proportional to 28.28, 42.40 and 21.48

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Solution

The fourth proportional to 28.28, 42.40 and 21.48 is: 32.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.28 : 42.40 = 21.48 : x
  2. Step 2: Convert to fraction form
    28.28/42.40 = 21.48/x
  3. Step 3: Cross multiply
    28.28x = 42.40 × 21.48
  4. Step 4: Simplify right side
    28.28x = 910.75
  5. Step 5: Solve for x
    x = 910.75/28.28
  6. Step 6: Final answer
    x = 32.20

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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.