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Finding the Fourth Proportional to 311.80, 430.12 and 213.60

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Solution

The fourth proportional to 311.80, 430.12 and 213.60 is: 294.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.80 : 430.12 = 213.60 : x
  2. Step 2: Convert to fraction form
    311.80/430.12 = 213.60/x
  3. Step 3: Cross multiply
    311.80x = 430.12 × 213.60
  4. Step 4: Simplify right side
    311.80x = 91,873.63
  5. Step 5: Solve for x
    x = 91,873.63/311.80
  6. Step 6: Final answer
    x = 294.66

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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.