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Finding the Fourth Proportional to 521.57, 719.76 and 288.70

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Solution

The fourth proportional to 521.57, 719.76 and 288.70 is: 398.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.57 : 719.76 = 288.70 : x
  2. Step 2: Convert to fraction form
    521.57/719.76 = 288.70/x
  3. Step 3: Cross multiply
    521.57x = 719.76 × 288.70
  4. Step 4: Simplify right side
    521.57x = 207,794.71
  5. Step 5: Solve for x
    x = 207,794.71/521.57
  6. Step 6: Final answer
    x = 398.40

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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.