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Finding the Fourth Proportional to 811.35, 1,216.39 and 400.20

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Solution

The fourth proportional to 811.35, 1,216.39 and 400.20 is: 599.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.35 : 1,216.39 = 400.20 : x
  2. Step 2: Convert to fraction form
    811.35/1,216.39 = 400.20/x
  3. Step 3: Cross multiply
    811.35x = 1,216.39 × 400.20
  4. Step 4: Simplify right side
    811.35x = 486,799.28
  5. Step 5: Solve for x
    x = 486,799.28/811.35
  6. Step 6: Final answer
    x = 599.99

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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.