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Finding the Fourth Proportional to 1,214.70, 1,821.15 and 520.80

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Solution

The fourth proportional to 1,214.70, 1,821.15 and 520.80 is: 780.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,214.70 : 1,821.15 = 520.80 : x
  2. Step 2: Convert to fraction form
    1,214.70/1,821.15 = 520.80/x
  3. Step 3: Cross multiply
    1,214.70x = 1,821.15 × 520.80
  4. Step 4: Simplify right side
    1,214.70x = 948,454.92
  5. Step 5: Solve for x
    x = 948,454.92/1,214.70
  6. Step 6: Final answer
    x = 780.81

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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.