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Finding the Fourth Proportional to 521.47, 719.62 and 311.78

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Solution

The fourth proportional to 521.47, 719.62 and 311.78 is: 430.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.47 : 719.62 = 311.78 : x
  2. Step 2: Convert to fraction form
    521.47/719.62 = 311.78/x
  3. Step 3: Cross multiply
    521.47x = 719.62 × 311.78
  4. Step 4: Simplify right side
    521.47x = 224,363.12
  5. Step 5: Solve for x
    x = 224,363.12/521.47
  6. Step 6: Final answer
    x = 430.25

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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.