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Finding the Fourth Proportional to 859.68, 1,290.42 and 513.72

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Solution

The fourth proportional to 859.68, 1,290.42 and 513.72 is: 771.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.68 : 1,290.42 = 513.72 : x
  2. Step 2: Convert to fraction form
    859.68/1,290.42 = 513.72/x
  3. Step 3: Cross multiply
    859.68x = 1,290.42 × 513.72
  4. Step 4: Simplify right side
    859.68x = 662,914.56
  5. Step 5: Solve for x
    x = 662,914.56/859.68
  6. Step 6: Final answer
    x = 771.12

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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.