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Finding the Fourth Proportional to 1,119.84, 1,679.70 and 389.20

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Solution

The fourth proportional to 1,119.84, 1,679.70 and 389.20 is: 583.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,119.84 : 1,679.70 = 389.20 : x
  2. Step 2: Convert to fraction form
    1,119.84/1,679.70 = 389.20/x
  3. Step 3: Cross multiply
    1,119.84x = 1,679.70 × 389.20
  4. Step 4: Simplify right side
    1,119.84x = 653,739.24
  5. Step 5: Solve for x
    x = 653,739.24/1,119.84
  6. Step 6: Final answer
    x = 583.78

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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.