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Finding the Fourth Proportional to 1,247.06, 1,720.87 and 687.56

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Solution

The fourth proportional to 1,247.06, 1,720.87 and 687.56 is: 948.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.06 : 1,720.87 = 687.56 : x
  2. Step 2: Convert to fraction form
    1,247.06/1,720.87 = 687.56/x
  3. Step 3: Cross multiply
    1,247.06x = 1,720.87 × 687.56
  4. Step 4: Simplify right side
    1,247.06x = 1,183,191.05
  5. Step 5: Solve for x
    x = 1,183,191.05/1,247.06
  6. Step 6: Final answer
    x = 948.78

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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.