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Finding the Fourth Proportional to 1,189.57, 1,641.65 and 665.57

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Solution

The fourth proportional to 1,189.57, 1,641.65 and 665.57 is: 918.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.57 : 1,641.65 = 665.57 : x
  2. Step 2: Convert to fraction form
    1,189.57/1,641.65 = 665.57/x
  3. Step 3: Cross multiply
    1,189.57x = 1,641.65 × 665.57
  4. Step 4: Simplify right side
    1,189.57x = 1,092,632.99
  5. Step 5: Solve for x
    x = 1,092,632.99/1,189.57
  6. Step 6: Final answer
    x = 918.51

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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.