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Finding the Fourth Proportional to 1,107.68, 1,528.62 and 642.20

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Solution

The fourth proportional to 1,107.68, 1,528.62 and 642.20 is: 886.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,107.68 : 1,528.62 = 642.20 : x
  2. Step 2: Convert to fraction form
    1,107.68/1,528.62 = 642.20/x
  3. Step 3: Cross multiply
    1,107.68x = 1,528.62 × 642.20
  4. Step 4: Simplify right side
    1,107.68x = 981,679.76
  5. Step 5: Solve for x
    x = 981,679.76/1,107.68
  6. Step 6: Final answer
    x = 886.25

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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.