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Finding the Fourth Proportional to 811.49, 1,121.37 and 664.07

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Solution

The fourth proportional to 811.49, 1,121.37 and 664.07 is: 917.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.49 : 1,121.37 = 664.07 : x
  2. Step 2: Convert to fraction form
    811.49/1,121.37 = 664.07/x
  3. Step 3: Cross multiply
    811.49x = 1,121.37 × 664.07
  4. Step 4: Simplify right side
    811.49x = 744,668.18
  5. Step 5: Solve for x
    x = 744,668.18/811.49
  6. Step 6: Final answer
    x = 917.66

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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.