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Finding the Fourth Proportional to 1,269.88, 1,902.36 and 720.40

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Solution

The fourth proportional to 1,269.88, 1,902.36 and 720.40 is: 1,079.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,269.88 : 1,902.36 = 720.40 : x
  2. Step 2: Convert to fraction form
    1,269.88/1,902.36 = 720.40/x
  3. Step 3: Cross multiply
    1,269.88x = 1,902.36 × 720.40
  4. Step 4: Simplify right side
    1,269.88x = 1,370,460.14
  5. Step 5: Solve for x
    x = 1,370,460.14/1,269.88
  6. Step 6: Final answer
    x = 1,079.20

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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.