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Finding the Fourth Proportional to 31.55, 47.20 and 20.08

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Solution

The fourth proportional to 31.55, 47.20 and 20.08 is: 30.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.55 : 47.20 = 20.08 : x
  2. Step 2: Convert to fraction form
    31.55/47.20 = 20.08/x
  3. Step 3: Cross multiply
    31.55x = 47.20 × 20.08
  4. Step 4: Simplify right side
    31.55x = 947.78
  5. Step 5: Solve for x
    x = 947.78/31.55
  6. Step 6: Final answer
    x = 30.04

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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.