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Finding the Fourth Proportional to 638.73, 881.30 and 390.03

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Solution

The fourth proportional to 638.73, 881.30 and 390.03 is: 538.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.73 : 881.30 = 390.03 : x
  2. Step 2: Convert to fraction form
    638.73/881.30 = 390.03/x
  3. Step 3: Cross multiply
    638.73x = 881.30 × 390.03
  4. Step 4: Simplify right side
    638.73x = 343,731.49
  5. Step 5: Solve for x
    x = 343,731.49/638.73
  6. Step 6: Final answer
    x = 538.15

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.