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Finding the Fourth Proportional to 1,389.15, 2,082.65 and 659.61

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Solution

The fourth proportional to 1,389.15, 2,082.65 and 659.61 is: 988.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.15 : 2,082.65 = 659.61 : x
  2. Step 2: Convert to fraction form
    1,389.15/2,082.65 = 659.61/x
  3. Step 3: Cross multiply
    1,389.15x = 2,082.65 × 659.61
  4. Step 4: Simplify right side
    1,389.15x = 1,373,733.47
  5. Step 5: Solve for x
    x = 1,373,733.47/1,389.15
  6. Step 6: Final answer
    x = 988.90

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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.