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Finding the Fourth Proportional to 311.40, 466.90 and 128.75

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Solution

The fourth proportional to 311.40, 466.90 and 128.75 is: 193.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.40 : 466.90 = 128.75 : x
  2. Step 2: Convert to fraction form
    311.40/466.90 = 128.75/x
  3. Step 3: Cross multiply
    311.40x = 466.90 × 128.75
  4. Step 4: Simplify right side
    311.40x = 60,110.72
  5. Step 5: Solve for x
    x = 60,110.72/311.40
  6. Step 6: Final answer
    x = 193.03

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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.