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Finding the Fourth Proportional to 311.50, 430.05 and 208.18

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Solution

The fourth proportional to 311.50, 430.05 and 208.18 is: 287.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.50 : 430.05 = 208.18 : x
  2. Step 2: Convert to fraction form
    311.50/430.05 = 208.18/x
  3. Step 3: Cross multiply
    311.50x = 430.05 × 208.18
  4. Step 4: Simplify right side
    311.50x = 89,527.81
  5. Step 5: Solve for x
    x = 89,527.81/311.50
  6. Step 6: Final answer
    x = 287.41

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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.