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Finding the Fourth Proportional to 687.25, 947.96 and 407.28

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Solution

The fourth proportional to 687.25, 947.96 and 407.28 is: 561.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.25 : 947.96 = 407.28 : x
  2. Step 2: Convert to fraction form
    687.25/947.96 = 407.28/x
  3. Step 3: Cross multiply
    687.25x = 947.96 × 407.28
  4. Step 4: Simplify right side
    687.25x = 386,084.01
  5. Step 5: Solve for x
    x = 386,084.01/687.25
  6. Step 6: Final answer
    x = 561.78

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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.