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Finding the Fourth Proportional to 810.09, 1,212.39 and 485.69

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Solution

The fourth proportional to 810.09, 1,212.39 and 485.69 is: 726.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.09 : 1,212.39 = 485.69 : x
  2. Step 2: Convert to fraction form
    810.09/1,212.39 = 485.69/x
  3. Step 3: Cross multiply
    810.09x = 1,212.39 × 485.69
  4. Step 4: Simplify right side
    810.09x = 588,839.64
  5. Step 5: Solve for x
    x = 588,839.64/810.09
  6. Step 6: Final answer
    x = 726.88

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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.