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Finding the Fourth Proportional to 1,119.40, 1,679.10 and 860.20

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Solution

The fourth proportional to 1,119.40, 1,679.10 and 860.20 is: 1,290.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,119.40 : 1,679.10 = 860.20 : x
  2. Step 2: Convert to fraction form
    1,119.40/1,679.10 = 860.20/x
  3. Step 3: Cross multiply
    1,119.40x = 1,679.10 × 860.20
  4. Step 4: Simplify right side
    1,119.40x = 1,444,361.82
  5. Step 5: Solve for x
    x = 1,444,361.82/1,119.40
  6. Step 6: Final answer
    x = 1,290.30

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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.