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Finding the Fourth Proportional to 520.78, 718.62 and 287.86

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Solution

The fourth proportional to 520.78, 718.62 and 287.86 is: 397.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.78 : 718.62 = 287.86 : x
  2. Step 2: Convert to fraction form
    520.78/718.62 = 287.86/x
  3. Step 3: Cross multiply
    520.78x = 718.62 × 287.86
  4. Step 4: Simplify right side
    520.78x = 206,861.95
  5. Step 5: Solve for x
    x = 206,861.95/520.78
  6. Step 6: Final answer
    x = 397.22

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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.