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Finding the Fourth Proportional to 1,280.75, 1,916.78 and 818.85

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Solution

The fourth proportional to 1,280.75, 1,916.78 and 818.85 is: 1,225.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.75 : 1,916.78 = 818.85 : x
  2. Step 2: Convert to fraction form
    1,280.75/1,916.78 = 818.85/x
  3. Step 3: Cross multiply
    1,280.75x = 1,916.78 × 818.85
  4. Step 4: Simplify right side
    1,280.75x = 1,569,551.21
  5. Step 5: Solve for x
    x = 1,569,551.21/1,280.75
  6. Step 6: Final answer
    x = 1,225.49

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1.5x scale

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.