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Finding the Fourth Proportional to 1,280.39, 1,767.08 and 720.87

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Solution

The fourth proportional to 1,280.39, 1,767.08 and 720.87 is: 994.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.39 : 1,767.08 = 720.87 : x
  2. Step 2: Convert to fraction form
    1,280.39/1,767.08 = 720.87/x
  3. Step 3: Cross multiply
    1,280.39x = 1,767.08 × 720.87
  4. Step 4: Simplify right side
    1,280.39x = 1,273,831.36
  5. Step 5: Solve for x
    x = 1,273,831.36/1,280.39
  6. Step 6: Final answer
    x = 994.88

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1.5x scale

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.