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Finding the Fourth Proportional to 521.78, 785.29 and 392.45

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Solution

The fourth proportional to 521.78, 785.29 and 392.45 is: 590.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.78 : 785.29 = 392.45 : x
  2. Step 2: Convert to fraction form
    521.78/785.29 = 392.45/x
  3. Step 3: Cross multiply
    521.78x = 785.29 × 392.45
  4. Step 4: Simplify right side
    521.78x = 308,187.31
  5. Step 5: Solve for x
    x = 308,187.31/521.78
  6. Step 6: Final answer
    x = 590.64

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.