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Finding the Fourth Proportional to 1,390.10, 2,082.31 and 657.45

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Solution

The fourth proportional to 1,390.10, 2,082.31 and 657.45 is: 984.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.10 : 2,082.31 = 657.45 : x
  2. Step 2: Convert to fraction form
    1,390.10/2,082.31 = 657.45/x
  3. Step 3: Cross multiply
    1,390.10x = 2,082.31 × 657.45
  4. Step 4: Simplify right side
    1,390.10x = 1,369,013.07
  5. Step 5: Solve for x
    x = 1,369,013.07/1,390.10
  6. Step 6: Final answer
    x = 984.83

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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.