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Finding the Fourth Proportional to 860.13, 1,290.81 and 665.61

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Solution

The fourth proportional to 860.13, 1,290.81 and 665.61 is: 998.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.13 : 1,290.81 = 665.61 : x
  2. Step 2: Convert to fraction form
    860.13/1,290.81 = 665.61/x
  3. Step 3: Cross multiply
    860.13x = 1,290.81 × 665.61
  4. Step 4: Simplify right side
    860.13x = 859,176.04
  5. Step 5: Solve for x
    x = 859,176.04/860.13
  6. Step 6: Final answer
    x = 998.89

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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.