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Finding the Fourth Proportional to 31.55, 47.30 and 18

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Solution

The fourth proportional to 31.55, 47.30 and 18 is: 26.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.55 : 47.30 = 18 : x
  2. Step 2: Convert to fraction form
    31.55/47.30 = 18/x
  3. Step 3: Cross multiply
    31.55x = 47.30 × 18
  4. Step 4: Simplify right side
    31.55x = 851.31
  5. Step 5: Solve for x
    x = 851.31/31.55
  6. Step 6: Final answer
    x = 26.99

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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.