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Finding the Fourth Proportional to 431.28, 646.80 and 214.80

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Solution

The fourth proportional to 431.28, 646.80 and 214.80 is: 322.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.28 : 646.80 = 214.80 : x
  2. Step 2: Convert to fraction form
    431.28/646.80 = 214.80/x
  3. Step 3: Cross multiply
    431.28x = 646.80 × 214.80
  4. Step 4: Simplify right side
    431.28x = 138,932.64
  5. Step 5: Solve for x
    x = 138,932.64/431.28
  6. Step 6: Final answer
    x = 322.14

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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.