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Finding the Fourth Proportional to 823.20, 1,135.89 and 491.64

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Solution

The fourth proportional to 823.20, 1,135.89 and 491.64 is: 678.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.20 : 1,135.89 = 491.64 : x
  2. Step 2: Convert to fraction form
    823.20/1,135.89 = 491.64/x
  3. Step 3: Cross multiply
    823.20x = 1,135.89 × 491.64
  4. Step 4: Simplify right side
    823.20x = 558,448.96
  5. Step 5: Solve for x
    x = 558,448.96/823.20
  6. Step 6: Final answer
    x = 678.39

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.