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Finding the Fourth Proportional to 431.30, 643.49 and 385.10

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Solution

The fourth proportional to 431.30, 643.49 and 385.10 is: 574.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.30 : 643.49 = 385.10 : x
  2. Step 2: Convert to fraction form
    431.30/643.49 = 385.10/x
  3. Step 3: Cross multiply
    431.30x = 643.49 × 385.10
  4. Step 4: Simplify right side
    431.30x = 247,806.07
  5. Step 5: Solve for x
    x = 247,806.07/431.30
  6. Step 6: Final answer
    x = 574.56

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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.