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Finding the Fourth Proportional to 1,305.21, 1,957.91 and 380.78

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Solution

The fourth proportional to 1,305.21, 1,957.91 and 380.78 is: 571.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,305.21 : 1,957.91 = 380.78 : x
  2. Step 2: Convert to fraction form
    1,305.21/1,957.91 = 380.78/x
  3. Step 3: Cross multiply
    1,305.21x = 1,957.91 × 380.78
  4. Step 4: Simplify right side
    1,305.21x = 745,521.28
  5. Step 5: Solve for x
    x = 745,521.28/1,305.21
  6. Step 6: Final answer
    x = 571.19

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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.