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Finding the Fourth Proportional to 811.60, 1,215.05 and 519.44

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Solution

The fourth proportional to 811.60, 1,215.05 and 519.44 is: 777.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.60 : 1,215.05 = 519.44 : x
  2. Step 2: Convert to fraction form
    811.60/1,215.05 = 519.44/x
  3. Step 3: Cross multiply
    811.60x = 1,215.05 × 519.44
  4. Step 4: Simplify right side
    811.60x = 631,136.90
  5. Step 5: Solve for x
    x = 631,136.90/811.60
  6. Step 6: Final answer
    x = 777.65

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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.