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Finding the Fourth Proportional to 860.57, 1,289.61 and 687.77

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Solution

The fourth proportional to 860.57, 1,289.61 and 687.77 is: 1,030.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.57 : 1,289.61 = 687.77 : x
  2. Step 2: Convert to fraction form
    860.57/1,289.61 = 687.77/x
  3. Step 3: Cross multiply
    860.57x = 1,289.61 × 687.77
  4. Step 4: Simplify right side
    860.57x = 886,948.62
  5. Step 5: Solve for x
    x = 886,948.62/860.57
  6. Step 6: Final answer
    x = 1,030.66

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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.