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Finding the Fourth Proportional to 815.25, 1,125.18 and 640.29

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Solution

The fourth proportional to 815.25, 1,125.18 and 640.29 is: 883.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.25 : 1,125.18 = 640.29 : x
  2. Step 2: Convert to fraction form
    815.25/1,125.18 = 640.29/x
  3. Step 3: Cross multiply
    815.25x = 1,125.18 × 640.29
  4. Step 4: Simplify right side
    815.25x = 720,441.50
  5. Step 5: Solve for x
    x = 720,441.50/815.25
  6. Step 6: Final answer
    x = 883.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.