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Finding the Fourth Proportional to 520.90, 780.96 and 212.68

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Solution

The fourth proportional to 520.90, 780.96 and 212.68 is: 318.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.90 : 780.96 = 212.68 : x
  2. Step 2: Convert to fraction form
    520.90/780.96 = 212.68/x
  3. Step 3: Cross multiply
    520.90x = 780.96 × 212.68
  4. Step 4: Simplify right side
    520.90x = 166,094.57
  5. Step 5: Solve for x
    x = 166,094.57/520.90
  6. Step 6: Final answer
    x = 318.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.