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Finding the Fourth Proportional to 842.20, 1,263.78 and 380

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Solution

The fourth proportional to 842.20, 1,263.78 and 380 is: 570.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.20 : 1,263.78 = 380 : x
  2. Step 2: Convert to fraction form
    842.20/1,263.78 = 380/x
  3. Step 3: Cross multiply
    842.20x = 1,263.78 × 380
  4. Step 4: Simplify right side
    842.20x = 480,236.40
  5. Step 5: Solve for x
    x = 480,236.40/842.20
  6. Step 6: Final answer
    x = 570.22

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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.