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Finding the Fourth Proportional to 521.19, 718.80 and 321.78

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Solution

The fourth proportional to 521.19, 718.80 and 321.78 is: 443.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.19 : 718.80 = 321.78 : x
  2. Step 2: Convert to fraction form
    521.19/718.80 = 321.78/x
  3. Step 3: Cross multiply
    521.19x = 718.80 × 321.78
  4. Step 4: Simplify right side
    521.19x = 231,295.46
  5. Step 5: Solve for x
    x = 231,295.46/521.19
  6. Step 6: Final answer
    x = 443.78

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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.