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Finding the Fourth Proportional to 817.30, 1,129.22 and 643.96

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Solution

The fourth proportional to 817.30, 1,129.22 and 643.96 is: 889.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.30 : 1,129.22 = 643.96 : x
  2. Step 2: Convert to fraction form
    817.30/1,129.22 = 643.96/x
  3. Step 3: Cross multiply
    817.30x = 1,129.22 × 643.96
  4. Step 4: Simplify right side
    817.30x = 727,172.51
  5. Step 5: Solve for x
    x = 727,172.51/817.30
  6. Step 6: Final answer
    x = 889.73

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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.