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Finding the Fourth Proportional to 520.10, 780.15 and 211.87

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Solution

The fourth proportional to 520.10, 780.15 and 211.87 is: 317.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.10 : 780.15 = 211.87 : x
  2. Step 2: Convert to fraction form
    520.10/780.15 = 211.87/x
  3. Step 3: Cross multiply
    520.10x = 780.15 × 211.87
  4. Step 4: Simplify right side
    520.10x = 165,290.31
  5. Step 5: Solve for x
    x = 165,290.31/520.10
  6. Step 6: Final answer
    x = 317.80

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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.