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Finding the Fourth Proportional to 431.11, 646.12 and 257.91

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Solution

The fourth proportional to 431.11, 646.12 and 257.91 is: 386.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.11 : 646.12 = 257.91 : x
  2. Step 2: Convert to fraction form
    431.11/646.12 = 257.91/x
  3. Step 3: Cross multiply
    431.11x = 646.12 × 257.91
  4. Step 4: Simplify right side
    431.11x = 166,640.81
  5. Step 5: Solve for x
    x = 166,640.81/431.11
  6. Step 6: Final answer
    x = 386.54

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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.