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Finding the Fourth Proportional to 811.96, 1,217.79 and 218.99

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Solution

The fourth proportional to 811.96, 1,217.79 and 218.99 is: 328.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.96 : 1,217.79 = 218.99 : x
  2. Step 2: Convert to fraction form
    811.96/1,217.79 = 218.99/x
  3. Step 3: Cross multiply
    811.96x = 1,217.79 × 218.99
  4. Step 4: Simplify right side
    811.96x = 266,677.74
  5. Step 5: Solve for x
    x = 266,677.74/811.96
  6. Step 6: Final answer
    x = 328.44

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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.