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Finding the Fourth Proportional to 815.30, 1,220.88 and 653.30

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Solution

The fourth proportional to 815.30, 1,220.88 and 653.30 is: 978.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.30 : 1,220.88 = 653.30 : x
  2. Step 2: Convert to fraction form
    815.30/1,220.88 = 653.30/x
  3. Step 3: Cross multiply
    815.30x = 1,220.88 × 653.30
  4. Step 4: Simplify right side
    815.30x = 797,600.90
  5. Step 5: Solve for x
    x = 797,600.90/815.30
  6. Step 6: Final answer
    x = 978.29

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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.