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Finding the Fourth Proportional to 520.78, 718.68 and 287.91

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Solution

The fourth proportional to 520.78, 718.68 and 287.91 is: 397.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.78 : 718.68 = 287.91 : x
  2. Step 2: Convert to fraction form
    520.78/718.68 = 287.91/x
  3. Step 3: Cross multiply
    520.78x = 718.68 × 287.91
  4. Step 4: Simplify right side
    520.78x = 206,915.16
  5. Step 5: Solve for x
    x = 206,915.16/520.78
  6. Step 6: Final answer
    x = 397.32

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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.