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Finding the Fourth Proportional to 1,138.25, 1,705.29 and 720.63

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Solution

The fourth proportional to 1,138.25, 1,705.29 and 720.63 is: 1,079.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.25 : 1,705.29 = 720.63 : x
  2. Step 2: Convert to fraction form
    1,138.25/1,705.29 = 720.63/x
  3. Step 3: Cross multiply
    1,138.25x = 1,705.29 × 720.63
  4. Step 4: Simplify right side
    1,138.25x = 1,228,880.43
  5. Step 5: Solve for x
    x = 1,228,880.43/1,138.25
  6. Step 6: Final answer
    x = 1,079.62

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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.