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Finding the Fourth Proportional to 31.60, 47.45 and 20.15

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Solution

The fourth proportional to 31.60, 47.45 and 20.15 is: 30.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.60 : 47.45 = 20.15 : x
  2. Step 2: Convert to fraction form
    31.60/47.45 = 20.15/x
  3. Step 3: Cross multiply
    31.60x = 47.45 × 20.15
  4. Step 4: Simplify right side
    31.60x = 956.02
  5. Step 5: Solve for x
    x = 956.02/31.60
  6. Step 6: Final answer
    x = 30.25

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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.