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Finding the Fourth Proportional to 1,385.81, 1,912.36 and 764.81

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Solution

The fourth proportional to 1,385.81, 1,912.36 and 764.81 is: 1,055.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,385.81 : 1,912.36 = 764.81 : x
  2. Step 2: Convert to fraction form
    1,385.81/1,912.36 = 764.81/x
  3. Step 3: Cross multiply
    1,385.81x = 1,912.36 × 764.81
  4. Step 4: Simplify right side
    1,385.81x = 1,462,592.05
  5. Step 5: Solve for x
    x = 1,462,592.05/1,385.81
  6. Step 6: Final answer
    x = 1,055.41

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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.