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Finding the Fourth Proportional to 639.06, 881.93 and 390.50

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Solution

The fourth proportional to 639.06, 881.93 and 390.50 is: 538.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.06 : 881.93 = 390.50 : x
  2. Step 2: Convert to fraction form
    639.06/881.93 = 390.50/x
  3. Step 3: Cross multiply
    639.06x = 881.93 × 390.50
  4. Step 4: Simplify right side
    639.06x = 344,388.77
  5. Step 5: Solve for x
    x = 344,388.77/639.06
  6. Step 6: Final answer
    x = 538.90

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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.