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Finding the Fourth Proportional to 811.20, 1,119.76 and 615.18

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Solution

The fourth proportional to 811.20, 1,119.76 and 615.18 is: 849.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,119.76 = 615.18 : x
  2. Step 2: Convert to fraction form
    811.20/1,119.76 = 615.18/x
  3. Step 3: Cross multiply
    811.20x = 1,119.76 × 615.18
  4. Step 4: Simplify right side
    811.20x = 688,853.96
  5. Step 5: Solve for x
    x = 688,853.96/811.20
  6. Step 6: Final answer
    x = 849.18

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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.