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Finding the Fourth Proportional to 1,219.12, 1,682.16 and 721.50

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Solution

The fourth proportional to 1,219.12, 1,682.16 and 721.50 is: 995.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,219.12 : 1,682.16 = 721.50 : x
  2. Step 2: Convert to fraction form
    1,219.12/1,682.16 = 721.50/x
  3. Step 3: Cross multiply
    1,219.12x = 1,682.16 × 721.50
  4. Step 4: Simplify right side
    1,219.12x = 1,213,678.44
  5. Step 5: Solve for x
    x = 1,213,678.44/1,219.12
  6. Step 6: Final answer
    x = 995.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.