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Finding the Fourth Proportional to 939.19, 1,405.62 and 720.13

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Solution

The fourth proportional to 939.19, 1,405.62 and 720.13 is: 1,077.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.19 : 1,405.62 = 720.13 : x
  2. Step 2: Convert to fraction form
    939.19/1,405.62 = 720.13/x
  3. Step 3: Cross multiply
    939.19x = 1,405.62 × 720.13
  4. Step 4: Simplify right side
    939.19x = 1,012,229.13
  5. Step 5: Solve for x
    x = 1,012,229.13/939.19
  6. Step 6: Final answer
    x = 1,077.77

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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.