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Finding the Fourth Proportional to 1,015.77, 1,520.21 and 645.40

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Solution

The fourth proportional to 1,015.77, 1,520.21 and 645.40 is: 965.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,015.77 : 1,520.21 = 645.40 : x
  2. Step 2: Convert to fraction form
    1,015.77/1,520.21 = 645.40/x
  3. Step 3: Cross multiply
    1,015.77x = 1,520.21 × 645.40
  4. Step 4: Simplify right side
    1,015.77x = 981,143.53
  5. Step 5: Solve for x
    x = 981,143.53/1,015.77
  6. Step 6: Final answer
    x = 965.91

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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.