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Finding the Fourth Proportional to 860.45, 1,289.66 and 397.80

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Solution

The fourth proportional to 860.45, 1,289.66 and 397.80 is: 596.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.45 : 1,289.66 = 397.80 : x
  2. Step 2: Convert to fraction form
    860.45/1,289.66 = 397.80/x
  3. Step 3: Cross multiply
    860.45x = 1,289.66 × 397.80
  4. Step 4: Simplify right side
    860.45x = 513,024.76
  5. Step 5: Solve for x
    x = 513,024.76/860.45
  6. Step 6: Final answer
    x = 596.23

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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.