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Finding the Fourth Proportional to 21.53, 29.70 and 15.38

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Solution

The fourth proportional to 21.53, 29.70 and 15.38 is: 21.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.53 : 29.70 = 15.38 : x
  2. Step 2: Convert to fraction form
    21.53/29.70 = 15.38/x
  3. Step 3: Cross multiply
    21.53x = 29.70 × 15.38
  4. Step 4: Simplify right side
    21.53x = 456.75
  5. Step 5: Solve for x
    x = 456.75/21.53
  6. Step 6: Final answer
    x = 21.21

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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.