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Finding the Fourth Proportional to 969.99, 1,338.21 and 638.58

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Solution

The fourth proportional to 969.99, 1,338.21 and 638.58 is: 880.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.99 : 1,338.21 = 638.58 : x
  2. Step 2: Convert to fraction form
    969.99/1,338.21 = 638.58/x
  3. Step 3: Cross multiply
    969.99x = 1,338.21 × 638.58
  4. Step 4: Simplify right side
    969.99x = 854,554.14
  5. Step 5: Solve for x
    x = 854,554.14/969.99
  6. Step 6: Final answer
    x = 880.99

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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.