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Finding the Fourth Proportional to 806.48, 1,115.18 and 640.40

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Solution

The fourth proportional to 806.48, 1,115.18 and 640.40 is: 885.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.48 : 1,115.18 = 640.40 : x
  2. Step 2: Convert to fraction form
    806.48/1,115.18 = 640.40/x
  3. Step 3: Cross multiply
    806.48x = 1,115.18 × 640.40
  4. Step 4: Simplify right side
    806.48x = 714,158.07
  5. Step 5: Solve for x
    x = 714,158.07/806.48
  6. Step 6: Final answer
    x = 885.52

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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.