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Finding the Fourth Proportional to 21.05, 31.53 and 10.20

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Solution

The fourth proportional to 21.05, 31.53 and 10.20 is: 15.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.05 : 31.53 = 10.20 : x
  2. Step 2: Convert to fraction form
    21.05/31.53 = 10.20/x
  3. Step 3: Cross multiply
    21.05x = 31.53 × 10.20
  4. Step 4: Simplify right side
    21.05x = 321.61
  5. Step 5: Solve for x
    x = 321.61/21.05
  6. Step 6: Final answer
    x = 15.28

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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.