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Finding the Fourth Proportional to 1,015.40, 1,520.40 and 648.20

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Solution

The fourth proportional to 1,015.40, 1,520.40 and 648.20 is: 970.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,015.40 : 1,520.40 = 648.20 : x
  2. Step 2: Convert to fraction form
    1,015.40/1,520.40 = 648.20/x
  3. Step 3: Cross multiply
    1,015.40x = 1,520.40 × 648.20
  4. Step 4: Simplify right side
    1,015.40x = 985,523.28
  5. Step 5: Solve for x
    x = 985,523.28/1,015.40
  6. Step 6: Final answer
    x = 970.58

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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.