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Finding the Fourth Proportional to 1,278.15, 1,916.49 and 619.80

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Solution

The fourth proportional to 1,278.15, 1,916.49 and 619.80 is: 929.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.15 : 1,916.49 = 619.80 : x
  2. Step 2: Convert to fraction form
    1,278.15/1,916.49 = 619.80/x
  3. Step 3: Cross multiply
    1,278.15x = 1,916.49 × 619.80
  4. Step 4: Simplify right side
    1,278.15x = 1,187,840.50
  5. Step 5: Solve for x
    x = 1,187,840.50/1,278.15
  6. Step 6: Final answer
    x = 929.34

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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.