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Finding the Fourth Proportional to 811.36, 1,214.72 and 485.76

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Solution

The fourth proportional to 811.36, 1,214.72 and 485.76 is: 727.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.36 : 1,214.72 = 485.76 : x
  2. Step 2: Convert to fraction form
    811.36/1,214.72 = 485.76/x
  3. Step 3: Cross multiply
    811.36x = 1,214.72 × 485.76
  4. Step 4: Simplify right side
    811.36x = 590,062.39
  5. Step 5: Solve for x
    x = 590,062.39/811.36
  6. Step 6: Final answer
    x = 727.25

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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.