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Finding the Fourth Proportional to 923.89, 1,272.67 and 643.63

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Solution

The fourth proportional to 923.89, 1,272.67 and 643.63 is: 886.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    923.89 : 1,272.67 = 643.63 : x
  2. Step 2: Convert to fraction form
    923.89/1,272.67 = 643.63/x
  3. Step 3: Cross multiply
    923.89x = 1,272.67 × 643.63
  4. Step 4: Simplify right side
    923.89x = 819,128.59
  5. Step 5: Solve for x
    x = 819,128.59/923.89
  6. Step 6: Final answer
    x = 886.61

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.