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Finding the Fourth Proportional to 811.83, 1,217.32 and 421.44

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Solution

The fourth proportional to 811.83, 1,217.32 and 421.44 is: 631.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.83 : 1,217.32 = 421.44 : x
  2. Step 2: Convert to fraction form
    811.83/1,217.32 = 421.44/x
  3. Step 3: Cross multiply
    811.83x = 1,217.32 × 421.44
  4. Step 4: Simplify right side
    811.83x = 513,025.23
  5. Step 5: Solve for x
    x = 513,025.23/811.83
  6. Step 6: Final answer
    x = 631.93

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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.