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Finding the Fourth Proportional to 639.95, 883.57 and 419.21

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Solution

The fourth proportional to 639.95, 883.57 and 419.21 is: 578.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.95 : 883.57 = 419.21 : x
  2. Step 2: Convert to fraction form
    639.95/883.57 = 419.21/x
  3. Step 3: Cross multiply
    639.95x = 883.57 × 419.21
  4. Step 4: Simplify right side
    639.95x = 370,395.91
  5. Step 5: Solve for x
    x = 370,395.91/639.95
  6. Step 6: Final answer
    x = 578.79

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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.