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Finding the Fourth Proportional to 806.40, 1,216.80 and 763.20

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Solution

The fourth proportional to 806.40, 1,216.80 and 763.20 is: 1,151.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.40 : 1,216.80 = 763.20 : x
  2. Step 2: Convert to fraction form
    806.40/1,216.80 = 763.20/x
  3. Step 3: Cross multiply
    806.40x = 1,216.80 × 763.20
  4. Step 4: Simplify right side
    806.40x = 928,661.76
  5. Step 5: Solve for x
    x = 928,661.76/806.40
  6. Step 6: Final answer
    x = 1,151.61

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.