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Finding the Fourth Proportional to 1,389.10, 2,082.72 and 658

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Solution

The fourth proportional to 1,389.10, 2,082.72 and 658 is: 986.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.10 : 2,082.72 = 658 : x
  2. Step 2: Convert to fraction form
    1,389.10/2,082.72 = 658/x
  3. Step 3: Cross multiply
    1,389.10x = 2,082.72 × 658
  4. Step 4: Simplify right side
    1,389.10x = 1,370,429.76
  5. Step 5: Solve for x
    x = 1,370,429.76/1,389.10
  6. Step 6: Final answer
    x = 986.56

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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.