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Finding the Fourth Proportional to 318.12, 438.90 and 187.11

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Solution

The fourth proportional to 318.12, 438.90 and 187.11 is: 258.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.12 : 438.90 = 187.11 : x
  2. Step 2: Convert to fraction form
    318.12/438.90 = 187.11/x
  3. Step 3: Cross multiply
    318.12x = 438.90 × 187.11
  4. Step 4: Simplify right side
    318.12x = 82,122.58
  5. Step 5: Solve for x
    x = 82,122.58/318.12
  6. Step 6: Final answer
    x = 258.15

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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.