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Finding the Fourth Proportional to 311.50, 466.80 and 128.80

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Solution

The fourth proportional to 311.50, 466.80 and 128.80 is: 193.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.50 : 466.80 = 128.80 : x
  2. Step 2: Convert to fraction form
    311.50/466.80 = 128.80/x
  3. Step 3: Cross multiply
    311.50x = 466.80 × 128.80
  4. Step 4: Simplify right side
    311.50x = 60,123.84
  5. Step 5: Solve for x
    x = 60,123.84/311.50
  6. Step 6: Final answer
    x = 193.01

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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.