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Finding the Fourth Proportional to 1,240.30, 1,861.80 and 778.60

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Solution

The fourth proportional to 1,240.30, 1,861.80 and 778.60 is: 1,168.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,240.30 : 1,861.80 = 778.60 : x
  2. Step 2: Convert to fraction form
    1,240.30/1,861.80 = 778.60/x
  3. Step 3: Cross multiply
    1,240.30x = 1,861.80 × 778.60
  4. Step 4: Simplify right side
    1,240.30x = 1,449,597.48
  5. Step 5: Solve for x
    x = 1,449,597.48/1,240.30
  6. Step 6: Final answer
    x = 1,168.75

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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.