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Finding the Fourth Proportional to 851.21, 1,276.85 and 389.01

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Solution

The fourth proportional to 851.21, 1,276.85 and 389.01 is: 583.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.21 : 1,276.85 = 389.01 : x
  2. Step 2: Convert to fraction form
    851.21/1,276.85 = 389.01/x
  3. Step 3: Cross multiply
    851.21x = 1,276.85 × 389.01
  4. Step 4: Simplify right side
    851.21x = 496,707.42
  5. Step 5: Solve for x
    x = 496,707.42/851.21
  6. Step 6: Final answer
    x = 583.53

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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.