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Finding the Fourth Proportional to 1,321.18, 1,978.93 and 772.82

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Solution

The fourth proportional to 1,321.18, 1,978.93 and 772.82 is: 1,157.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.18 : 1,978.93 = 772.82 : x
  2. Step 2: Convert to fraction form
    1,321.18/1,978.93 = 772.82/x
  3. Step 3: Cross multiply
    1,321.18x = 1,978.93 × 772.82
  4. Step 4: Simplify right side
    1,321.18x = 1,529,356.68
  5. Step 5: Solve for x
    x = 1,529,356.68/1,321.18
  6. Step 6: Final answer
    x = 1,157.57

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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.