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Finding the Fourth Proportional to 643.56, 888.21 and 407.70

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Solution

The fourth proportional to 643.56, 888.21 and 407.70 is: 562.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.56 : 888.21 = 407.70 : x
  2. Step 2: Convert to fraction form
    643.56/888.21 = 407.70/x
  3. Step 3: Cross multiply
    643.56x = 888.21 × 407.70
  4. Step 4: Simplify right side
    643.56x = 362,123.22
  5. Step 5: Solve for x
    x = 362,123.22/643.56
  6. Step 6: Final answer
    x = 562.69

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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.