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Finding the Fourth Proportional to 431.28, 646.20 and 429.12

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Solution

The fourth proportional to 431.28, 646.20 and 429.12 is: 642.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.28 : 646.20 = 429.12 : x
  2. Step 2: Convert to fraction form
    431.28/646.20 = 429.12/x
  3. Step 3: Cross multiply
    431.28x = 646.20 × 429.12
  4. Step 4: Simplify right side
    431.28x = 277,297.34
  5. Step 5: Solve for x
    x = 277,297.34/431.28
  6. Step 6: Final answer
    x = 642.96

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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.