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Finding the Fourth Proportional to 806.40, 1,112.64 and 491.64

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Solution

The fourth proportional to 806.40, 1,112.64 and 491.64 is: 678.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.40 : 1,112.64 = 491.64 : x
  2. Step 2: Convert to fraction form
    806.40/1,112.64 = 491.64/x
  3. Step 3: Cross multiply
    806.40x = 1,112.64 × 491.64
  4. Step 4: Simplify right side
    806.40x = 547,018.33
  5. Step 5: Solve for x
    x = 547,018.33/806.40
  6. Step 6: Final answer
    x = 678.35

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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.