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Finding the Fourth Proportional to 1,212.64, 1,819.80 and 665.20

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Solution

The fourth proportional to 1,212.64, 1,819.80 and 665.20 is: 998.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.64 : 1,819.80 = 665.20 : x
  2. Step 2: Convert to fraction form
    1,212.64/1,819.80 = 665.20/x
  3. Step 3: Cross multiply
    1,212.64x = 1,819.80 × 665.20
  4. Step 4: Simplify right side
    1,212.64x = 1,210,530.96
  5. Step 5: Solve for x
    x = 1,210,530.96/1,212.64
  6. Step 6: Final answer
    x = 998.26

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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.