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Finding the Fourth Proportional to 638.66, 881.23 and 390.06

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Solution

The fourth proportional to 638.66, 881.23 and 390.06 is: 538.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.66 : 881.23 = 390.06 : x
  2. Step 2: Convert to fraction form
    638.66/881.23 = 390.06/x
  3. Step 3: Cross multiply
    638.66x = 881.23 × 390.06
  4. Step 4: Simplify right side
    638.66x = 343,732.57
  5. Step 5: Solve for x
    x = 343,732.57/638.66
  6. Step 6: Final answer
    x = 538.21

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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.