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Finding the Fourth Proportional to 825.64, 1,238.40 and 312.28

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Solution

The fourth proportional to 825.64, 1,238.40 and 312.28 is: 468.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.64 : 1,238.40 = 312.28 : x
  2. Step 2: Convert to fraction form
    825.64/1,238.40 = 312.28/x
  3. Step 3: Cross multiply
    825.64x = 1,238.40 × 312.28
  4. Step 4: Simplify right side
    825.64x = 386,727.55
  5. Step 5: Solve for x
    x = 386,727.55/825.64
  6. Step 6: Final answer
    x = 468.40

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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.