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Finding the Fourth Proportional to 25.90, 38.85 and 21.90

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Solution

The fourth proportional to 25.90, 38.85 and 21.90 is: 32.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.90 : 38.85 = 21.90 : x
  2. Step 2: Convert to fraction form
    25.90/38.85 = 21.90/x
  3. Step 3: Cross multiply
    25.90x = 38.85 × 21.90
  4. Step 4: Simplify right side
    25.90x = 850.82
  5. Step 5: Solve for x
    x = 850.82/25.90
  6. Step 6: Final answer
    x = 32.85

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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.