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Finding the Fourth Proportional to 639.23, 881.98 and 390.53

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Solution

The fourth proportional to 639.23, 881.98 and 390.53 is: 538.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.23 : 881.98 = 390.53 : x
  2. Step 2: Convert to fraction form
    639.23/881.98 = 390.53/x
  3. Step 3: Cross multiply
    639.23x = 881.98 × 390.53
  4. Step 4: Simplify right side
    639.23x = 344,439.65
  5. Step 5: Solve for x
    x = 344,439.65/639.23
  6. Step 6: Final answer
    x = 538.84

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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.