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Finding the Fourth Proportional to 906.80, 1,358.40 and 615.20

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Solution

The fourth proportional to 906.80, 1,358.40 and 615.20 is: 921.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    906.80 : 1,358.40 = 615.20 : x
  2. Step 2: Convert to fraction form
    906.80/1,358.40 = 615.20/x
  3. Step 3: Cross multiply
    906.80x = 1,358.40 × 615.20
  4. Step 4: Simplify right side
    906.80x = 835,687.68
  5. Step 5: Solve for x
    x = 835,687.68/906.80
  6. Step 6: Final answer
    x = 921.58

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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.