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Finding the Fourth Proportional to 21.55, 29.72 and 14.28

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Solution

The fourth proportional to 21.55, 29.72 and 14.28 is: 19.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.55 : 29.72 = 14.28 : x
  2. Step 2: Convert to fraction form
    21.55/29.72 = 14.28/x
  3. Step 3: Cross multiply
    21.55x = 29.72 × 14.28
  4. Step 4: Simplify right side
    21.55x = 424.44
  5. Step 5: Solve for x
    x = 424.44/21.55
  6. Step 6: Final answer
    x = 19.70

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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.