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Finding the Fourth Proportional to 815.68, 1,221.90 and 506.80

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Solution

The fourth proportional to 815.68, 1,221.90 and 506.80 is: 759.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.68 : 1,221.90 = 506.80 : x
  2. Step 2: Convert to fraction form
    815.68/1,221.90 = 506.80/x
  3. Step 3: Cross multiply
    815.68x = 1,221.90 × 506.80
  4. Step 4: Simplify right side
    815.68x = 619,258.92
  5. Step 5: Solve for x
    x = 619,258.92/815.68
  6. Step 6: Final answer
    x = 759.19

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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.