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Finding the Fourth Proportional to 521.70, 719.78 and 311.91

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Solution

The fourth proportional to 521.70, 719.78 and 311.91 is: 430.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.70 : 719.78 = 311.91 : x
  2. Step 2: Convert to fraction form
    521.70/719.78 = 311.91/x
  3. Step 3: Cross multiply
    521.70x = 719.78 × 311.91
  4. Step 4: Simplify right side
    521.70x = 224,505.02
  5. Step 5: Solve for x
    x = 224,505.02/521.70
  6. Step 6: Final answer
    x = 430.33

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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.