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Finding the Fourth Proportional to 860.94, 1,287.47 and 641.72

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Solution

The fourth proportional to 860.94, 1,287.47 and 641.72 is: 959.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.94 : 1,287.47 = 641.72 : x
  2. Step 2: Convert to fraction form
    860.94/1,287.47 = 641.72/x
  3. Step 3: Cross multiply
    860.94x = 1,287.47 × 641.72
  4. Step 4: Simplify right side
    860.94x = 826,194.19
  5. Step 5: Solve for x
    x = 826,194.19/860.94
  6. Step 6: Final answer
    x = 959.64

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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.