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Finding the Fourth Proportional to 207.42, 311.09 and 85.53

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Solution

The fourth proportional to 207.42, 311.09 and 85.53 is: 128.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.42 : 311.09 = 85.53 : x
  2. Step 2: Convert to fraction form
    207.42/311.09 = 85.53/x
  3. Step 3: Cross multiply
    207.42x = 311.09 × 85.53
  4. Step 4: Simplify right side
    207.42x = 26,608.27
  5. Step 5: Solve for x
    x = 26,608.27/207.42
  6. Step 6: Final answer
    x = 128.28

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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.