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Finding the Fourth Proportional to 687.75, 948.65 and 407.78

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Solution

The fourth proportional to 687.75, 948.65 and 407.78 is: 562.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.75 : 948.65 = 407.78 : x
  2. Step 2: Convert to fraction form
    687.75/948.65 = 407.78/x
  3. Step 3: Cross multiply
    687.75x = 948.65 × 407.78
  4. Step 4: Simplify right side
    687.75x = 386,840.50
  5. Step 5: Solve for x
    x = 386,840.50/687.75
  6. Step 6: Final answer
    x = 562.47

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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.