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Finding the Fourth Proportional to 20.51, 28.31 and 11.30

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Solution

The fourth proportional to 20.51, 28.31 and 11.30 is: 15.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.51 : 28.31 = 11.30 : x
  2. Step 2: Convert to fraction form
    20.51/28.31 = 11.30/x
  3. Step 3: Cross multiply
    20.51x = 28.31 × 11.30
  4. Step 4: Simplify right side
    20.51x = 320.02
  5. Step 5: Solve for x
    x = 320.02/20.51
  6. Step 6: Final answer
    x = 15.60

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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.