Home / 1,120.10-1,680.30-389.90

Finding the Fourth Proportional to 1,120.10, 1,680.30 and 389.90

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Solution

The fourth proportional to 1,120.10, 1,680.30 and 389.90 is: 584.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120.10 : 1,680.30 = 389.90 : x
  2. Step 2: Convert to fraction form
    1,120.10/1,680.30 = 389.90/x
  3. Step 3: Cross multiply
    1,120.10x = 1,680.30 × 389.90
  4. Step 4: Simplify right side
    1,120.10x = 655,148.97
  5. Step 5: Solve for x
    x = 655,148.97/1,120.10
  6. Step 6: Final answer
    x = 584.90

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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.