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Finding the Fourth Proportional to 642.42, 964.80 and 399.42

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Solution

The fourth proportional to 642.42, 964.80 and 399.42 is: 599.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.42 : 964.80 = 399.42 : x
  2. Step 2: Convert to fraction form
    642.42/964.80 = 399.42/x
  3. Step 3: Cross multiply
    642.42x = 964.80 × 399.42
  4. Step 4: Simplify right side
    642.42x = 385,360.42
  5. Step 5: Solve for x
    x = 385,360.42/642.42
  6. Step 6: Final answer
    x = 599.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.