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Finding the Fourth Proportional to 1,325.55, 1,989.04 and 778.80

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Solution

The fourth proportional to 1,325.55, 1,989.04 and 778.80 is: 1,168.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,325.55 : 1,989.04 = 778.80 : x
  2. Step 2: Convert to fraction form
    1,325.55/1,989.04 = 778.80/x
  3. Step 3: Cross multiply
    1,325.55x = 1,989.04 × 778.80
  4. Step 4: Simplify right side
    1,325.55x = 1,549,064.35
  5. Step 5: Solve for x
    x = 1,549,064.35/1,325.55
  6. Step 6: Final answer
    x = 1,168.62

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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.