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Finding the Fourth Proportional to 431.05, 646.79 and 211.81

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Solution

The fourth proportional to 431.05, 646.79 and 211.81 is: 317.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.05 : 646.79 = 211.81 : x
  2. Step 2: Convert to fraction form
    431.05/646.79 = 211.81/x
  3. Step 3: Cross multiply
    431.05x = 646.79 × 211.81
  4. Step 4: Simplify right side
    431.05x = 136,996.59
  5. Step 5: Solve for x
    x = 136,996.59/431.05
  6. Step 6: Final answer
    x = 317.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.