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Finding the Fourth Proportional to 819.07, 1,221.69 and 687.53

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Solution

The fourth proportional to 819.07, 1,221.69 and 687.53 is: 1,025.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.07 : 1,221.69 = 687.53 : x
  2. Step 2: Convert to fraction form
    819.07/1,221.69 = 687.53/x
  3. Step 3: Cross multiply
    819.07x = 1,221.69 × 687.53
  4. Step 4: Simplify right side
    819.07x = 839,950.29
  5. Step 5: Solve for x
    x = 839,950.29/819.07
  6. Step 6: Final answer
    x = 1,025.50

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.