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Finding the Fourth Proportional to 1,369.40, 2,055.90 and 638.58

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Solution

The fourth proportional to 1,369.40, 2,055.90 and 638.58 is: 958.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,369.40 : 2,055.90 = 638.58 : x
  2. Step 2: Convert to fraction form
    1,369.40/2,055.90 = 638.58/x
  3. Step 3: Cross multiply
    1,369.40x = 2,055.90 × 638.58
  4. Step 4: Simplify right side
    1,369.40x = 1,312,856.62
  5. Step 5: Solve for x
    x = 1,312,856.62/1,369.40
  6. Step 6: Final answer
    x = 958.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.