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Finding the Fourth Proportional to 1,189.60, 1,641.70 and 665.64

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Solution

The fourth proportional to 1,189.60, 1,641.70 and 665.64 is: 918.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.60 : 1,641.70 = 665.64 : x
  2. Step 2: Convert to fraction form
    1,189.60/1,641.70 = 665.64/x
  3. Step 3: Cross multiply
    1,189.60x = 1,641.70 × 665.64
  4. Step 4: Simplify right side
    1,189.60x = 1,092,781.19
  5. Step 5: Solve for x
    x = 1,092,781.19/1,189.60
  6. Step 6: Final answer
    x = 918.61

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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.