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Finding the Fourth Proportional to 287.20, 428.09 and 275.05

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Solution

The fourth proportional to 287.20, 428.09 and 275.05 is: 409.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.20 : 428.09 = 275.05 : x
  2. Step 2: Convert to fraction form
    287.20/428.09 = 275.05/x
  3. Step 3: Cross multiply
    287.20x = 428.09 × 275.05
  4. Step 4: Simplify right side
    287.20x = 117,746.15
  5. Step 5: Solve for x
    x = 117,746.15/287.20
  6. Step 6: Final answer
    x = 409.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.