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Finding the Fourth Proportional to 639.90, 883.17 and 419.45

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Solution

The fourth proportional to 639.90, 883.17 and 419.45 is: 578.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.90 : 883.17 = 419.45 : x
  2. Step 2: Convert to fraction form
    639.90/883.17 = 419.45/x
  3. Step 3: Cross multiply
    639.90x = 883.17 × 419.45
  4. Step 4: Simplify right side
    639.90x = 370,441.24
  5. Step 5: Solve for x
    x = 370,441.24/639.90
  6. Step 6: Final answer
    x = 578.90

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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.