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Finding the Fourth Proportional to 969.88, 1,337.80 and 638.72

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Solution

The fourth proportional to 969.88, 1,337.80 and 638.72 is: 881.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.88 : 1,337.80 = 638.72 : x
  2. Step 2: Convert to fraction form
    969.88/1,337.80 = 638.72/x
  3. Step 3: Cross multiply
    969.88x = 1,337.80 × 638.72
  4. Step 4: Simplify right side
    969.88x = 854,479.62
  5. Step 5: Solve for x
    x = 854,479.62/969.88
  6. Step 6: Final answer
    x = 881.02

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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.