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Finding the Fourth Proportional to 31.68, 43.72 and 30.88

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Solution

The fourth proportional to 31.68, 43.72 and 30.88 is: 42.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.68 : 43.72 = 30.88 : x
  2. Step 2: Convert to fraction form
    31.68/43.72 = 30.88/x
  3. Step 3: Cross multiply
    31.68x = 43.72 × 30.88
  4. Step 4: Simplify right side
    31.68x = 1,350.07
  5. Step 5: Solve for x
    x = 1,350.07/31.68
  6. Step 6: Final answer
    x = 42.62

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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.