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Finding the Fourth Proportional to 840.68, 1,161.57 and 811.11

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Solution

The fourth proportional to 840.68, 1,161.57 and 811.11 is: 1,120.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.68 : 1,161.57 = 811.11 : x
  2. Step 2: Convert to fraction form
    840.68/1,161.57 = 811.11/x
  3. Step 3: Cross multiply
    840.68x = 1,161.57 × 811.11
  4. Step 4: Simplify right side
    840.68x = 942,161.04
  5. Step 5: Solve for x
    x = 942,161.04/840.68
  6. Step 6: Final answer
    x = 1,120.72

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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.