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Finding the Fourth Proportional to 411.40, 621.56 and 407.75

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Solution

The fourth proportional to 411.40, 621.56 and 407.75 is: 616.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    411.40 : 621.56 = 407.75 : x
  2. Step 2: Convert to fraction form
    411.40/621.56 = 407.75/x
  3. Step 3: Cross multiply
    411.40x = 621.56 × 407.75
  4. Step 4: Simplify right side
    411.40x = 253,440.20
  5. Step 5: Solve for x
    x = 253,440.20/411.40
  6. Step 6: Final answer
    x = 616.05

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.