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Finding the Fourth Proportional to 211.87, 315.29 and 209.59

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Solution

The fourth proportional to 211.87, 315.29 and 209.59 is: 311.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.87 : 315.29 = 209.59 : x
  2. Step 2: Convert to fraction form
    211.87/315.29 = 209.59/x
  3. Step 3: Cross multiply
    211.87x = 315.29 × 209.59
  4. Step 4: Simplify right side
    211.87x = 66,081.37
  5. Step 5: Solve for x
    x = 66,081.37/211.87
  6. Step 6: Final answer
    x = 311.90

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.