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Finding the Fourth Proportional to 31.17, 43.02 and 18.90

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Solution

The fourth proportional to 31.17, 43.02 and 18.90 is: 26.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.17 : 43.02 = 18.90 : x
  2. Step 2: Convert to fraction form
    31.17/43.02 = 18.90/x
  3. Step 3: Cross multiply
    31.17x = 43.02 × 18.90
  4. Step 4: Simplify right side
    31.17x = 813.08
  5. Step 5: Solve for x
    x = 813.08/31.17
  6. Step 6: Final answer
    x = 26.09

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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.