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Finding the Fourth Proportional to 1,191.28, 1,786.92 and 643.72

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Solution

The fourth proportional to 1,191.28, 1,786.92 and 643.72 is: 965.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,191.28 : 1,786.92 = 643.72 : x
  2. Step 2: Convert to fraction form
    1,191.28/1,786.92 = 643.72/x
  3. Step 3: Cross multiply
    1,191.28x = 1,786.92 × 643.72
  4. Step 4: Simplify right side
    1,191.28x = 1,150,276.14
  5. Step 5: Solve for x
    x = 1,150,276.14/1,191.28
  6. Step 6: Final answer
    x = 965.58

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.