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Finding the Fourth Proportional to 811.60, 1,121.04 and 681.28

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Solution

The fourth proportional to 811.60, 1,121.04 and 681.28 is: 941.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.60 : 1,121.04 = 681.28 : x
  2. Step 2: Convert to fraction form
    811.60/1,121.04 = 681.28/x
  3. Step 3: Cross multiply
    811.60x = 1,121.04 × 681.28
  4. Step 4: Simplify right side
    811.60x = 763,742.13
  5. Step 5: Solve for x
    x = 763,742.13/811.60
  6. Step 6: Final answer
    x = 941.03

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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.