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Finding the Fourth Proportional to 1,386.39, 2,079.60 and 520.50

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Solution

The fourth proportional to 1,386.39, 2,079.60 and 520.50 is: 780.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.39 : 2,079.60 = 520.50 : x
  2. Step 2: Convert to fraction form
    1,386.39/2,079.60 = 520.50/x
  3. Step 3: Cross multiply
    1,386.39x = 2,079.60 × 520.50
  4. Step 4: Simplify right side
    1,386.39x = 1,082,431.80
  5. Step 5: Solve for x
    x = 1,082,431.80/1,386.39
  6. Step 6: Final answer
    x = 780.76

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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.