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Finding the Fourth Proportional to 1,386, 2,079.41 and 520.38

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Solution

The fourth proportional to 1,386, 2,079.41 and 520.38 is: 780.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386 : 2,079.41 = 520.38 : x
  2. Step 2: Convert to fraction form
    1,386/2,079.41 = 520.38/x
  3. Step 3: Cross multiply
    1,386x = 2,079.41 × 520.38
  4. Step 4: Simplify right side
    1,386x = 1,082,083.38
  5. Step 5: Solve for x
    x = 1,082,083.38/1,386
  6. Step 6: Final answer
    x = 780.72

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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.