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Finding the Fourth Proportional to 989.06, 1,364.93 and 640.36

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Solution

The fourth proportional to 989.06, 1,364.93 and 640.36 is: 883.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.06 : 1,364.93 = 640.36 : x
  2. Step 2: Convert to fraction form
    989.06/1,364.93 = 640.36/x
  3. Step 3: Cross multiply
    989.06x = 1,364.93 × 640.36
  4. Step 4: Simplify right side
    989.06x = 874,044.76
  5. Step 5: Solve for x
    x = 874,044.76/989.06
  6. Step 6: Final answer
    x = 883.71

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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.