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Finding the Fourth Proportional to 852.30, 1,278.54 and 390.20

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Solution

The fourth proportional to 852.30, 1,278.54 and 390.20 is: 585.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    852.30 : 1,278.54 = 390.20 : x
  2. Step 2: Convert to fraction form
    852.30/1,278.54 = 390.20/x
  3. Step 3: Cross multiply
    852.30x = 1,278.54 × 390.20
  4. Step 4: Simplify right side
    852.30x = 498,879.92
  5. Step 5: Solve for x
    x = 498,879.92/852.30
  6. Step 6: Final answer
    x = 585.33

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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.