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Finding the Fourth Proportional to 852.72, 1,278.12 and 420.18

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Solution

The fourth proportional to 852.72, 1,278.12 and 420.18 is: 629.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    852.72 : 1,278.12 = 420.18 : x
  2. Step 2: Convert to fraction form
    852.72/1,278.12 = 420.18/x
  3. Step 3: Cross multiply
    852.72x = 1,278.12 × 420.18
  4. Step 4: Simplify right side
    852.72x = 537,040.46
  5. Step 5: Solve for x
    x = 537,040.46/852.72
  6. Step 6: Final answer
    x = 629.80

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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.