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Finding the Fourth Proportional to 431.33, 643.69 and 385.20

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Solution

The fourth proportional to 431.33, 643.69 and 385.20 is: 574.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.33 : 643.69 = 385.20 : x
  2. Step 2: Convert to fraction form
    431.33/643.69 = 385.20/x
  3. Step 3: Cross multiply
    431.33x = 643.69 × 385.20
  4. Step 4: Simplify right side
    431.33x = 247,948.43
  5. Step 5: Solve for x
    x = 247,948.43/431.33
  6. Step 6: Final answer
    x = 574.84

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.