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Finding the Fourth Proportional to 821.64, 1,231.09 and 577.65

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Solution

The fourth proportional to 821.64, 1,231.09 and 577.65 is: 865.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.64 : 1,231.09 = 577.65 : x
  2. Step 2: Convert to fraction form
    821.64/1,231.09 = 577.65/x
  3. Step 3: Cross multiply
    821.64x = 1,231.09 × 577.65
  4. Step 4: Simplify right side
    821.64x = 711,139.14
  5. Step 5: Solve for x
    x = 711,139.14/821.64
  6. Step 6: Final answer
    x = 865.51

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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.