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Finding the Fourth Proportional to 815.20, 1,222.56 and 653.20

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Solution

The fourth proportional to 815.20, 1,222.56 and 653.20 is: 979.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.20 : 1,222.56 = 653.20 : x
  2. Step 2: Convert to fraction form
    815.20/1,222.56 = 653.20/x
  3. Step 3: Cross multiply
    815.20x = 1,222.56 × 653.20
  4. Step 4: Simplify right side
    815.20x = 798,576.19
  5. Step 5: Solve for x
    x = 798,576.19/815.20
  6. Step 6: Final answer
    x = 979.61

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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.