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Finding the Fourth Proportional to 1,212.90, 1,820.15 and 665.47

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Solution

The fourth proportional to 1,212.90, 1,820.15 and 665.47 is: 998.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.90 : 1,820.15 = 665.47 : x
  2. Step 2: Convert to fraction form
    1,212.90/1,820.15 = 665.47/x
  3. Step 3: Cross multiply
    1,212.90x = 1,820.15 × 665.47
  4. Step 4: Simplify right side
    1,212.90x = 1,211,255.22
  5. Step 5: Solve for x
    x = 1,211,255.22/1,212.90
  6. Step 6: Final answer
    x = 998.64

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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.