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Finding the Fourth Proportional to 909.21, 1,363.80 and 389.55

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Solution

The fourth proportional to 909.21, 1,363.80 and 389.55 is: 584.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.21 : 1,363.80 = 389.55 : x
  2. Step 2: Convert to fraction form
    909.21/1,363.80 = 389.55/x
  3. Step 3: Cross multiply
    909.21x = 1,363.80 × 389.55
  4. Step 4: Simplify right side
    909.21x = 531,268.29
  5. Step 5: Solve for x
    x = 531,268.29/909.21
  6. Step 6: Final answer
    x = 584.32

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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.