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Finding the Fourth Proportional to 858.72, 1,286.02 and 815.66

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Solution

The fourth proportional to 858.72, 1,286.02 and 815.66 is: 1,221.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.72 : 1,286.02 = 815.66 : x
  2. Step 2: Convert to fraction form
    858.72/1,286.02 = 815.66/x
  3. Step 3: Cross multiply
    858.72x = 1,286.02 × 815.66
  4. Step 4: Simplify right side
    858.72x = 1,048,954.49
  5. Step 5: Solve for x
    x = 1,048,954.49/858.72
  6. Step 6: Final answer
    x = 1,221.53

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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.