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Finding the Fourth Proportional to 815.35, 1,221.68 and 677.65

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Solution

The fourth proportional to 815.35, 1,221.68 and 677.65 is: 1,015.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.35 : 1,221.68 = 677.65 : x
  2. Step 2: Convert to fraction form
    815.35/1,221.68 = 677.65/x
  3. Step 3: Cross multiply
    815.35x = 1,221.68 × 677.65
  4. Step 4: Simplify right side
    815.35x = 827,868.06
  5. Step 5: Solve for x
    x = 827,868.06/815.35
  6. Step 6: Final answer
    x = 1,015.35

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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.