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Finding the Fourth Proportional to 1,391.61, 2,085.36 and 659.66

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Solution

The fourth proportional to 1,391.61, 2,085.36 and 659.66 is: 988.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.61 : 2,085.36 = 659.66 : x
  2. Step 2: Convert to fraction form
    1,391.61/2,085.36 = 659.66/x
  3. Step 3: Cross multiply
    1,391.61x = 2,085.36 × 659.66
  4. Step 4: Simplify right side
    1,391.61x = 1,375,618.15
  5. Step 5: Solve for x
    x = 1,375,618.15/1,391.61
  6. Step 6: Final answer
    x = 988.51

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.