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Finding the Fourth Proportional to 22.78, 31.25 and 21.40

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Solution

The fourth proportional to 22.78, 31.25 and 21.40 is: 29.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    22.78 : 31.25 = 21.40 : x
  2. Step 2: Convert to fraction form
    22.78/31.25 = 21.40/x
  3. Step 3: Cross multiply
    22.78x = 31.25 × 21.40
  4. Step 4: Simplify right side
    22.78x = 668.75
  5. Step 5: Solve for x
    x = 668.75/22.78
  6. Step 6: Final answer
    x = 29.36

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.