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Finding the Fourth Proportional to 1,378.56, 1,901.16 and 912

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Solution

The fourth proportional to 1,378.56, 1,901.16 and 912 is: 1,257.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.56 : 1,901.16 = 912 : x
  2. Step 2: Convert to fraction form
    1,378.56/1,901.16 = 912/x
  3. Step 3: Cross multiply
    1,378.56x = 1,901.16 × 912
  4. Step 4: Simplify right side
    1,378.56x = 1,733,857.92
  5. Step 5: Solve for x
    x = 1,733,857.92/1,378.56
  6. Step 6: Final answer
    x = 1,257.73

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.