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Finding the Fourth Proportional to 993.50, 1,369.78 and 638.80

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Solution

The fourth proportional to 993.50, 1,369.78 and 638.80 is: 880.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    993.50 : 1,369.78 = 638.80 : x
  2. Step 2: Convert to fraction form
    993.50/1,369.78 = 638.80/x
  3. Step 3: Cross multiply
    993.50x = 1,369.78 × 638.80
  4. Step 4: Simplify right side
    993.50x = 875,015.46
  5. Step 5: Solve for x
    x = 875,015.46/993.50
  6. Step 6: Final answer
    x = 880.74

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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.