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Finding the Fourth Proportional to 990.70, 1,369.77 and 867.68

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Solution

The fourth proportional to 990.70, 1,369.77 and 867.68 is: 1,199.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.70 : 1,369.77 = 867.68 : x
  2. Step 2: Convert to fraction form
    990.70/1,369.77 = 867.68/x
  3. Step 3: Cross multiply
    990.70x = 1,369.77 × 867.68
  4. Step 4: Simplify right side
    990.70x = 1,188,515.18
  5. Step 5: Solve for x
    x = 1,188,515.18/990.70
  6. Step 6: Final answer
    x = 1,199.68

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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.