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Finding the Fourth Proportional to 811.32, 1,121.22 and 663.72

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Solution

The fourth proportional to 811.32, 1,121.22 and 663.72 is: 917.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.32 : 1,121.22 = 663.72 : x
  2. Step 2: Convert to fraction form
    811.32/1,121.22 = 663.72/x
  3. Step 3: Cross multiply
    811.32x = 1,121.22 × 663.72
  4. Step 4: Simplify right side
    811.32x = 744,176.14
  5. Step 5: Solve for x
    x = 744,176.14/811.32
  6. Step 6: Final answer
    x = 917.24

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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.