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Finding the Fourth Proportional to 311.81, 430.26 and 218.66

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Solution

The fourth proportional to 311.81, 430.26 and 218.66 is: 301.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.81 : 430.26 = 218.66 : x
  2. Step 2: Convert to fraction form
    311.81/430.26 = 218.66/x
  3. Step 3: Cross multiply
    311.81x = 430.26 × 218.66
  4. Step 4: Simplify right side
    311.81x = 94,080.65
  5. Step 5: Solve for x
    x = 94,080.65/311.81
  6. Step 6: Final answer
    x = 301.72

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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.