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Finding the Fourth Proportional to 1,120.29, 1,680.65 and 389.89

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Solution

The fourth proportional to 1,120.29, 1,680.65 and 389.89 is: 584.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120.29 : 1,680.65 = 389.89 : x
  2. Step 2: Convert to fraction form
    1,120.29/1,680.65 = 389.89/x
  3. Step 3: Cross multiply
    1,120.29x = 1,680.65 × 389.89
  4. Step 4: Simplify right side
    1,120.29x = 655,268.63
  5. Step 5: Solve for x
    x = 655,268.63/1,120.29
  6. Step 6: Final answer
    x = 584.91

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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.