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Finding the Fourth Proportional to 1,278.16, 1,916.64 and 809.76

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Solution

The fourth proportional to 1,278.16, 1,916.64 and 809.76 is: 1,214.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.16 : 1,916.64 = 809.76 : x
  2. Step 2: Convert to fraction form
    1,278.16/1,916.64 = 809.76/x
  3. Step 3: Cross multiply
    1,278.16x = 1,916.64 × 809.76
  4. Step 4: Simplify right side
    1,278.16x = 1,552,018.41
  5. Step 5: Solve for x
    x = 1,552,018.41/1,278.16
  6. Step 6: Final answer
    x = 1,214.26

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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.