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Finding the Fourth Proportional to 684.30, 1,025.75 and 391.70

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Solution

The fourth proportional to 684.30, 1,025.75 and 391.70 is: 587.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.30 : 1,025.75 = 391.70 : x
  2. Step 2: Convert to fraction form
    684.30/1,025.75 = 391.70/x
  3. Step 3: Cross multiply
    684.30x = 1,025.75 × 391.70
  4. Step 4: Simplify right side
    684.30x = 401,782.13
  5. Step 5: Solve for x
    x = 401,782.13/684.30
  6. Step 6: Final answer
    x = 587.15

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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.