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Finding the Fourth Proportional to 904.20, 1,247.79 and 511.21

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Solution

The fourth proportional to 904.20, 1,247.79 and 511.21 is: 705.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    904.20 : 1,247.79 = 511.21 : x
  2. Step 2: Convert to fraction form
    904.20/1,247.79 = 511.21/x
  3. Step 3: Cross multiply
    904.20x = 1,247.79 × 511.21
  4. Step 4: Simplify right side
    904.20x = 637,882.73
  5. Step 5: Solve for x
    x = 637,882.73/904.20
  6. Step 6: Final answer
    x = 705.47

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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.