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Finding the Fourth Proportional to 1,389.25, 2,083.87 and 638.67

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Solution

The fourth proportional to 1,389.25, 2,083.87 and 638.67 is: 958.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.25 : 2,083.87 = 638.67 : x
  2. Step 2: Convert to fraction form
    1,389.25/2,083.87 = 638.67/x
  3. Step 3: Cross multiply
    1,389.25x = 2,083.87 × 638.67
  4. Step 4: Simplify right side
    1,389.25x = 1,330,902.46
  5. Step 5: Solve for x
    x = 1,330,902.46/1,389.25
  6. Step 6: Final answer
    x = 958.00

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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.