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Finding the Fourth Proportional to 307.80, 424.64 and 287.15

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Solution

The fourth proportional to 307.80, 424.64 and 287.15 is: 396.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    307.80 : 424.64 = 287.15 : x
  2. Step 2: Convert to fraction form
    307.80/424.64 = 287.15/x
  3. Step 3: Cross multiply
    307.80x = 424.64 × 287.15
  4. Step 4: Simplify right side
    307.80x = 121,933.97
  5. Step 5: Solve for x
    x = 121,933.97/307.80
  6. Step 6: Final answer
    x = 396.15

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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.