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Finding the Fourth Proportional to 1,855.40, 2,778.60 and 987.80

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Solution

The fourth proportional to 1,855.40, 2,778.60 and 987.80 is: 1,479.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,855.40 : 2,778.60 = 987.80 : x
  2. Step 2: Convert to fraction form
    1,855.40/2,778.60 = 987.80/x
  3. Step 3: Cross multiply
    1,855.40x = 2,778.60 × 987.80
  4. Step 4: Simplify right side
    1,855.40x = 2,744,701.08
  5. Step 5: Solve for x
    x = 2,744,701.08/1,855.40
  6. Step 6: Final answer
    x = 1,479.30

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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.