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Finding the Fourth Proportional to 816.72, 1,219.94 and 687.12

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Solution

The fourth proportional to 816.72, 1,219.94 and 687.12 is: 1,026.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.72 : 1,219.94 = 687.12 : x
  2. Step 2: Convert to fraction form
    816.72/1,219.94 = 687.12/x
  3. Step 3: Cross multiply
    816.72x = 1,219.94 × 687.12
  4. Step 4: Simplify right side
    816.72x = 838,245.17
  5. Step 5: Solve for x
    x = 838,245.17/816.72
  6. Step 6: Final answer
    x = 1,026.36

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.