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Finding the Fourth Proportional to 816.91, 1,126.60 and 641.95

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Solution

The fourth proportional to 816.91, 1,126.60 and 641.95 is: 885.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.91 : 1,126.60 = 641.95 : x
  2. Step 2: Convert to fraction form
    816.91/1,126.60 = 641.95/x
  3. Step 3: Cross multiply
    816.91x = 1,126.60 × 641.95
  4. Step 4: Simplify right side
    816.91x = 723,216.45
  5. Step 5: Solve for x
    x = 723,216.45/816.91
  6. Step 6: Final answer
    x = 885.31

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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.