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Finding the Fourth Proportional to 811.36, 1,120.20 and 723.88

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Solution

The fourth proportional to 811.36, 1,120.20 and 723.88 is: 999.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.36 : 1,120.20 = 723.88 : x
  2. Step 2: Convert to fraction form
    811.36/1,120.20 = 723.88/x
  3. Step 3: Cross multiply
    811.36x = 1,120.20 × 723.88
  4. Step 4: Simplify right side
    811.36x = 810,890.38
  5. Step 5: Solve for x
    x = 810,890.38/811.36
  6. Step 6: Final answer
    x = 999.42

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1.5x scale

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.