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Finding the Fourth Proportional to 21.25, 31.90 and 10.59

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Solution

The fourth proportional to 21.25, 31.90 and 10.59 is: 15.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.25 : 31.90 = 10.59 : x
  2. Step 2: Convert to fraction form
    21.25/31.90 = 10.59/x
  3. Step 3: Cross multiply
    21.25x = 31.90 × 10.59
  4. Step 4: Simplify right side
    21.25x = 337.82
  5. Step 5: Solve for x
    x = 337.82/21.25
  6. Step 6: Final answer
    x = 15.90

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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.