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Finding the Fourth Proportional to 859.47, 1,290.12 and 513.21

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Solution

The fourth proportional to 859.47, 1,290.12 and 513.21 is: 770.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.47 : 1,290.12 = 513.21 : x
  2. Step 2: Convert to fraction form
    859.47/1,290.12 = 513.21/x
  3. Step 3: Cross multiply
    859.47x = 1,290.12 × 513.21
  4. Step 4: Simplify right side
    859.47x = 662,102.49
  5. Step 5: Solve for x
    x = 662,102.49/859.47
  6. Step 6: Final answer
    x = 770.36

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Double scale
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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.