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Finding the Fourth Proportional to 311.51, 429.75 and 211.81

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Solution

The fourth proportional to 311.51, 429.75 and 211.81 is: 292.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.51 : 429.75 = 211.81 : x
  2. Step 2: Convert to fraction form
    311.51/429.75 = 211.81/x
  3. Step 3: Cross multiply
    311.51x = 429.75 × 211.81
  4. Step 4: Simplify right side
    311.51x = 91,022.14
  5. Step 5: Solve for x
    x = 91,022.14/311.51
  6. Step 6: Final answer
    x = 292.20

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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.