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Finding the Fourth Proportional to 815.87, 1,221.38 and 786.71

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Solution

The fourth proportional to 815.87, 1,221.38 and 786.71 is: 1,177.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.87 : 1,221.38 = 786.71 : x
  2. Step 2: Convert to fraction form
    815.87/1,221.38 = 786.71/x
  3. Step 3: Cross multiply
    815.87x = 1,221.38 × 786.71
  4. Step 4: Simplify right side
    815.87x = 960,867.93
  5. Step 5: Solve for x
    x = 960,867.93/815.87
  6. Step 6: Final answer
    x = 1,177.72

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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.