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Finding the Fourth Proportional to 688.53, 949.77 and 642.09

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Solution

The fourth proportional to 688.53, 949.77 and 642.09 is: 885.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.53 : 949.77 = 642.09 : x
  2. Step 2: Convert to fraction form
    688.53/949.77 = 642.09/x
  3. Step 3: Cross multiply
    688.53x = 949.77 × 642.09
  4. Step 4: Simplify right side
    688.53x = 609,837.82
  5. Step 5: Solve for x
    x = 609,837.82/688.53
  6. Step 6: Final answer
    x = 885.71

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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.