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Finding the Fourth Proportional to 919.78, 1,267.81 and 720.27

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Solution

The fourth proportional to 919.78, 1,267.81 and 720.27 is: 992.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.78 : 1,267.81 = 720.27 : x
  2. Step 2: Convert to fraction form
    919.78/1,267.81 = 720.27/x
  3. Step 3: Cross multiply
    919.78x = 1,267.81 × 720.27
  4. Step 4: Simplify right side
    919.78x = 913,165.51
  5. Step 5: Solve for x
    x = 913,165.51/919.78
  6. Step 6: Final answer
    x = 992.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.