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Finding the Fourth Proportional to 811.70, 1,216.20 and 763.10

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Solution

The fourth proportional to 811.70, 1,216.20 and 763.10 is: 1,143.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.70 : 1,216.20 = 763.10 : x
  2. Step 2: Convert to fraction form
    811.70/1,216.20 = 763.10/x
  3. Step 3: Cross multiply
    811.70x = 1,216.20 × 763.10
  4. Step 4: Simplify right side
    811.70x = 928,082.22
  5. Step 5: Solve for x
    x = 928,082.22/811.70
  6. Step 6: Final answer
    x = 1,143.38

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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.