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Finding the Fourth Proportional to 919.90, 1,291.10 and 919.90

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Solution

The fourth proportional to 919.90, 1,291.10 and 919.90 is: 1,291.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.90 : 1,291.10 = 919.90 : x
  2. Step 2: Convert to fraction form
    919.90/1,291.10 = 919.90/x
  3. Step 3: Cross multiply
    919.90x = 1,291.10 × 919.90
  4. Step 4: Simplify right side
    919.90x = 1,187,682.89
  5. Step 5: Solve for x
    x = 1,187,682.89/919.90
  6. Step 6: Final answer
    x = 1,291.10

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Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.