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Finding the Fourth Proportional to 811.20, 1,216.66 and 291.12

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Solution

The fourth proportional to 811.20, 1,216.66 and 291.12 is: 436.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,216.66 = 291.12 : x
  2. Step 2: Convert to fraction form
    811.20/1,216.66 = 291.12/x
  3. Step 3: Cross multiply
    811.20x = 1,216.66 × 291.12
  4. Step 4: Simplify right side
    811.20x = 354,194.06
  5. Step 5: Solve for x
    x = 354,194.06/811.20
  6. Step 6: Final answer
    x = 436.63

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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.