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Finding the Fourth Proportional to 1,309.92, 1,965.16 and 385.40

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Solution

The fourth proportional to 1,309.92, 1,965.16 and 385.40 is: 578.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.92 : 1,965.16 = 385.40 : x
  2. Step 2: Convert to fraction form
    1,309.92/1,965.16 = 385.40/x
  3. Step 3: Cross multiply
    1,309.92x = 1,965.16 × 385.40
  4. Step 4: Simplify right side
    1,309.92x = 757,376.61
  5. Step 5: Solve for x
    x = 757,376.61/1,309.92
  6. Step 6: Final answer
    x = 578.18

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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.