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Finding the Fourth Proportional to 31.15, 43.00 and 18.90

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Solution

The fourth proportional to 31.15, 43.00 and 18.90 is: 26.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.15 : 43.00 = 18.90 : x
  2. Step 2: Convert to fraction form
    31.15/43.00 = 18.90/x
  3. Step 3: Cross multiply
    31.15x = 43.00 × 18.90
  4. Step 4: Simplify right side
    31.15x = 812.65
  5. Step 5: Solve for x
    x = 812.65/31.15
  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.