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Finding the Fourth Proportional to 1,216.81, 1,679.34 and 685.78

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Solution

The fourth proportional to 1,216.81, 1,679.34 and 685.78 is: 946.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,216.81 : 1,679.34 = 685.78 : x
  2. Step 2: Convert to fraction form
    1,216.81/1,679.34 = 685.78/x
  3. Step 3: Cross multiply
    1,216.81x = 1,679.34 × 685.78
  4. Step 4: Simplify right side
    1,216.81x = 1,151,657.79
  5. Step 5: Solve for x
    x = 1,151,657.79/1,216.81
  6. Step 6: Final answer
    x = 946.46

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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.