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Finding the Fourth Proportional to 816.90, 1,218.86 and 708.90

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Solution

The fourth proportional to 816.90, 1,218.86 and 708.90 is: 1,057.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.90 : 1,218.86 = 708.90 : x
  2. Step 2: Convert to fraction form
    816.90/1,218.86 = 708.90/x
  3. Step 3: Cross multiply
    816.90x = 1,218.86 × 708.90
  4. Step 4: Simplify right side
    816.90x = 864,046.31
  5. Step 5: Solve for x
    x = 864,046.31/816.90
  6. Step 6: Final answer
    x = 1,057.71

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.