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Finding the Fourth Proportional to 1,311.74, 1,809.74 and 839.71

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Solution

The fourth proportional to 1,311.74, 1,809.74 and 839.71 is: 1,158.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.74 : 1,809.74 = 839.71 : x
  2. Step 2: Convert to fraction form
    1,311.74/1,809.74 = 839.71/x
  3. Step 3: Cross multiply
    1,311.74x = 1,809.74 × 839.71
  4. Step 4: Simplify right side
    1,311.74x = 1,519,656.78
  5. Step 5: Solve for x
    x = 1,519,656.78/1,311.74
  6. Step 6: Final answer
    x = 1,158.50

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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.