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Finding the Fourth Proportional to 20.55, 30.75 and 11.50

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Solution

The fourth proportional to 20.55, 30.75 and 11.50 is: 17.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.55 : 30.75 = 11.50 : x
  2. Step 2: Convert to fraction form
    20.55/30.75 = 11.50/x
  3. Step 3: Cross multiply
    20.55x = 30.75 × 11.50
  4. Step 4: Simplify right side
    20.55x = 353.63
  5. Step 5: Solve for x
    x = 353.63/20.55
  6. Step 6: Final answer
    x = 17.21

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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.