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Finding the Fourth Proportional to 989.28, 1,364.31 and 872.64

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Solution

The fourth proportional to 989.28, 1,364.31 and 872.64 is: 1,203.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.28 : 1,364.31 = 872.64 : x
  2. Step 2: Convert to fraction form
    989.28/1,364.31 = 872.64/x
  3. Step 3: Cross multiply
    989.28x = 1,364.31 × 872.64
  4. Step 4: Simplify right side
    989.28x = 1,190,551.48
  5. Step 5: Solve for x
    x = 1,190,551.48/989.28
  6. Step 6: Final answer
    x = 1,203.45

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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.