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Finding the Fourth Proportional to 512.40, 707.64 and 394.80

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Solution

The fourth proportional to 512.40, 707.64 and 394.80 is: 545.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.40 : 707.64 = 394.80 : x
  2. Step 2: Convert to fraction form
    512.40/707.64 = 394.80/x
  3. Step 3: Cross multiply
    512.40x = 707.64 × 394.80
  4. Step 4: Simplify right side
    512.40x = 279,376.27
  5. Step 5: Solve for x
    x = 279,376.27/512.40
  6. Step 6: Final answer
    x = 545.23

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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.