Home / 1,122.20-1,680.10-690.20

Finding the Fourth Proportional to 1,122.20, 1,680.10 and 690.20

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Solution

The fourth proportional to 1,122.20, 1,680.10 and 690.20 is: 1,033.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,122.20 : 1,680.10 = 690.20 : x
  2. Step 2: Convert to fraction form
    1,122.20/1,680.10 = 690.20/x
  3. Step 3: Cross multiply
    1,122.20x = 1,680.10 × 690.20
  4. Step 4: Simplify right side
    1,122.20x = 1,159,605.02
  5. Step 5: Solve for x
    x = 1,159,605.02/1,122.20
  6. Step 6: Final answer
    x = 1,033.33

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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.