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Finding the Fourth Proportional to 1,278.40, 1,915.71 and 730.75

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Solution

The fourth proportional to 1,278.40, 1,915.71 and 730.75 is: 1,095.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.40 : 1,915.71 = 730.75 : x
  2. Step 2: Convert to fraction form
    1,278.40/1,915.71 = 730.75/x
  3. Step 3: Cross multiply
    1,278.40x = 1,915.71 × 730.75
  4. Step 4: Simplify right side
    1,278.40x = 1,399,905.08
  5. Step 5: Solve for x
    x = 1,399,905.08/1,278.40
  6. Step 6: Final answer
    x = 1,095.04

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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.