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Finding the Fourth Proportional to 521.74, 720.05 and 288.90

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Solution

The fourth proportional to 521.74, 720.05 and 288.90 is: 398.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.74 : 720.05 = 288.90 : x
  2. Step 2: Convert to fraction form
    521.74/720.05 = 288.90/x
  3. Step 3: Cross multiply
    521.74x = 720.05 × 288.90
  4. Step 4: Simplify right side
    521.74x = 208,022.45
  5. Step 5: Solve for x
    x = 208,022.45/521.74
  6. Step 6: Final answer
    x = 398.71

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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.