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Finding the Fourth Proportional to 671.91, 1,007.90 and 209.75

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Solution

The fourth proportional to 671.91, 1,007.90 and 209.75 is: 314.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    671.91 : 1,007.90 = 209.75 : x
  2. Step 2: Convert to fraction form
    671.91/1,007.90 = 209.75/x
  3. Step 3: Cross multiply
    671.91x = 1,007.90 × 209.75
  4. Step 4: Simplify right side
    671.91x = 211,410.07
  5. Step 5: Solve for x
    x = 211,410.07/671.91
  6. Step 6: Final answer
    x = 314.64

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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.