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Finding the Fourth Proportional to 1,119.80, 1,679.98 and 389.39

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Solution

The fourth proportional to 1,119.80, 1,679.98 and 389.39 is: 584.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,119.80 : 1,679.98 = 389.39 : x
  2. Step 2: Convert to fraction form
    1,119.80/1,679.98 = 389.39/x
  3. Step 3: Cross multiply
    1,119.80x = 1,679.98 × 389.39
  4. Step 4: Simplify right side
    1,119.80x = 654,159.86
  5. Step 5: Solve for x
    x = 654,159.86/1,119.80
  6. Step 6: Final answer
    x = 584.17

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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.