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Finding the Fourth Proportional to 811.10, 1,216.71 and 291.20

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Solution

The fourth proportional to 811.10, 1,216.71 and 291.20 is: 436.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.10 : 1,216.71 = 291.20 : x
  2. Step 2: Convert to fraction form
    811.10/1,216.71 = 291.20/x
  3. Step 3: Cross multiply
    811.10x = 1,216.71 × 291.20
  4. Step 4: Simplify right side
    811.10x = 354,305.95
  5. Step 5: Solve for x
    x = 354,305.95/811.10
  6. Step 6: Final answer
    x = 436.82

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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.