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Finding the Fourth Proportional to 521.40, 781.52 and 261.08

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Solution

The fourth proportional to 521.40, 781.52 and 261.08 is: 391.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.40 : 781.52 = 261.08 : x
  2. Step 2: Convert to fraction form
    521.40/781.52 = 261.08/x
  3. Step 3: Cross multiply
    521.40x = 781.52 × 261.08
  4. Step 4: Simplify right side
    521.40x = 204,034.03
  5. Step 5: Solve for x
    x = 204,034.03/521.40
  6. Step 6: Final answer
    x = 391.32

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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.