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Finding the Fourth Proportional to 31.04, 42.84 and 20.68

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Solution

The fourth proportional to 31.04, 42.84 and 20.68 is: 28.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.04 : 42.84 = 20.68 : x
  2. Step 2: Convert to fraction form
    31.04/42.84 = 20.68/x
  3. Step 3: Cross multiply
    31.04x = 42.84 × 20.68
  4. Step 4: Simplify right side
    31.04x = 885.72
  5. Step 5: Solve for x
    x = 885.72/31.04
  6. Step 6: Final answer
    x = 28.53

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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.