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Finding the Fourth Proportional to 812.34, 1,121.40 and 666.54

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Solution

The fourth proportional to 812.34, 1,121.40 and 666.54 is: 920.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.34 : 1,121.40 = 666.54 : x
  2. Step 2: Convert to fraction form
    812.34/1,121.40 = 666.54/x
  3. Step 3: Cross multiply
    812.34x = 1,121.40 × 666.54
  4. Step 4: Simplify right side
    812.34x = 747,457.96
  5. Step 5: Solve for x
    x = 747,457.96/812.34
  6. Step 6: Final answer
    x = 920.13

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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.