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Finding the Fourth Proportional to 380.90, 571.35 and 120.90

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Solution

The fourth proportional to 380.90, 571.35 and 120.90 is: 181.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    380.90 : 571.35 = 120.90 : x
  2. Step 2: Convert to fraction form
    380.90/571.35 = 120.90/x
  3. Step 3: Cross multiply
    380.90x = 571.35 × 120.90
  4. Step 4: Simplify right side
    380.90x = 69,076.22
  5. Step 5: Solve for x
    x = 69,076.22/380.90
  6. Step 6: Final answer
    x = 181.35

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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.