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Finding the Fourth Proportional to 812.79, 1,121.94 and 648.18

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Solution

The fourth proportional to 812.79, 1,121.94 and 648.18 is: 894.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.79 : 1,121.94 = 648.18 : x
  2. Step 2: Convert to fraction form
    812.79/1,121.94 = 648.18/x
  3. Step 3: Cross multiply
    812.79x = 1,121.94 × 648.18
  4. Step 4: Simplify right side
    812.79x = 727,219.07
  5. Step 5: Solve for x
    x = 727,219.07/812.79
  6. Step 6: Final answer
    x = 894.72

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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.