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Finding the Fourth Proportional to 639.56, 959.72 and 419.66

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Solution

The fourth proportional to 639.56, 959.72 and 419.66 is: 629.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.56 : 959.72 = 419.66 : x
  2. Step 2: Convert to fraction form
    639.56/959.72 = 419.66/x
  3. Step 3: Cross multiply
    639.56x = 959.72 × 419.66
  4. Step 4: Simplify right side
    639.56x = 402,756.10
  5. Step 5: Solve for x
    x = 402,756.10/639.56
  6. Step 6: Final answer
    x = 629.74

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.