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Finding the Fourth Proportional to 1,188.30, 1,639.68 and 664.30

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Solution

The fourth proportional to 1,188.30, 1,639.68 and 664.30 is: 916.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.30 : 1,639.68 = 664.30 : x
  2. Step 2: Convert to fraction form
    1,188.30/1,639.68 = 664.30/x
  3. Step 3: Cross multiply
    1,188.30x = 1,639.68 × 664.30
  4. Step 4: Simplify right side
    1,188.30x = 1,089,239.42
  5. Step 5: Solve for x
    x = 1,089,239.42/1,188.30
  6. Step 6: Final answer
    x = 916.64

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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.