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Finding the Fourth Proportional to 207.40, 311.22 and 91.90

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Solution

The fourth proportional to 207.40, 311.22 and 91.90 is: 137.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.40 : 311.22 = 91.90 : x
  2. Step 2: Convert to fraction form
    207.40/311.22 = 91.90/x
  3. Step 3: Cross multiply
    207.40x = 311.22 × 91.90
  4. Step 4: Simplify right side
    207.40x = 28,601.12
  5. Step 5: Solve for x
    x = 28,601.12/207.40
  6. Step 6: Final answer
    x = 137.90

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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.