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Finding the Fourth Proportional to 1,188.28, 1,639.83 and 664.31

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Solution

The fourth proportional to 1,188.28, 1,639.83 and 664.31 is: 916.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.28 : 1,639.83 = 664.31 : x
  2. Step 2: Convert to fraction form
    1,188.28/1,639.83 = 664.31/x
  3. Step 3: Cross multiply
    1,188.28x = 1,639.83 × 664.31
  4. Step 4: Simplify right side
    1,188.28x = 1,089,362.06
  5. Step 5: Solve for x
    x = 1,089,362.06/1,188.28
  6. Step 6: Final answer
    x = 916.75

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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.