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Finding the Fourth Proportional to 681.66, 1,017.90 and 643.26

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Solution

The fourth proportional to 681.66, 1,017.90 and 643.26 is: 960.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.66 : 1,017.90 = 643.26 : x
  2. Step 2: Convert to fraction form
    681.66/1,017.90 = 643.26/x
  3. Step 3: Cross multiply
    681.66x = 1,017.90 × 643.26
  4. Step 4: Simplify right side
    681.66x = 654,774.35
  5. Step 5: Solve for x
    x = 654,774.35/681.66
  6. Step 6: Final answer
    x = 960.56

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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.