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Finding the Fourth Proportional to 639.18, 957.86 and 314.78

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Solution

The fourth proportional to 639.18, 957.86 and 314.78 is: 471.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.18 : 957.86 = 314.78 : x
  2. Step 2: Convert to fraction form
    639.18/957.86 = 314.78/x
  3. Step 3: Cross multiply
    639.18x = 957.86 × 314.78
  4. Step 4: Simplify right side
    639.18x = 301,509.99
  5. Step 5: Solve for x
    x = 301,509.99/639.18
  6. Step 6: Final answer
    x = 471.71

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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.