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Finding the Fourth Proportional to 811.64, 1,217.60 and 263.81

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Solution

The fourth proportional to 811.64, 1,217.60 and 263.81 is: 395.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.64 : 1,217.60 = 263.81 : x
  2. Step 2: Convert to fraction form
    811.64/1,217.60 = 263.81/x
  3. Step 3: Cross multiply
    811.64x = 1,217.60 × 263.81
  4. Step 4: Simplify right side
    811.64x = 321,215.06
  5. Step 5: Solve for x
    x = 321,215.06/811.64
  6. Step 6: Final answer
    x = 395.76

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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.