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Finding the Fourth Proportional to 812.35, 1,121.70 and 771.58

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Solution

The fourth proportional to 812.35, 1,121.70 and 771.58 is: 1,065.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.35 : 1,121.70 = 771.58 : x
  2. Step 2: Convert to fraction form
    812.35/1,121.70 = 771.58/x
  3. Step 3: Cross multiply
    812.35x = 1,121.70 × 771.58
  4. Step 4: Simplify right side
    812.35x = 865,481.29
  5. Step 5: Solve for x
    x = 865,481.29/812.35
  6. Step 6: Final answer
    x = 1,065.40

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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.