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Finding the Fourth Proportional to 864.15, 1,290.75 and 620.55

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Solution

The fourth proportional to 864.15, 1,290.75 and 620.55 is: 926.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.15 : 1,290.75 = 620.55 : x
  2. Step 2: Convert to fraction form
    864.15/1,290.75 = 620.55/x
  3. Step 3: Cross multiply
    864.15x = 1,290.75 × 620.55
  4. Step 4: Simplify right side
    864.15x = 800,974.91
  5. Step 5: Solve for x
    x = 800,974.91/864.15
  6. Step 6: Final answer
    x = 926.89

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.