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Finding the Fourth Proportional to 810.15, 1,213.61 and 728.21

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Solution

The fourth proportional to 810.15, 1,213.61 and 728.21 is: 1,090.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.15 : 1,213.61 = 728.21 : x
  2. Step 2: Convert to fraction form
    810.15/1,213.61 = 728.21/x
  3. Step 3: Cross multiply
    810.15x = 1,213.61 × 728.21
  4. Step 4: Simplify right side
    810.15x = 883,753.23
  5. Step 5: Solve for x
    x = 883,753.23/810.15
  6. Step 6: Final answer
    x = 1,090.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.