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Finding the Fourth Proportional to 642.68, 964.08 and 209.88

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Solution

The fourth proportional to 642.68, 964.08 and 209.88 is: 314.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.68 : 964.08 = 209.88 : x
  2. Step 2: Convert to fraction form
    642.68/964.08 = 209.88/x
  3. Step 3: Cross multiply
    642.68x = 964.08 × 209.88
  4. Step 4: Simplify right side
    642.68x = 202,341.11
  5. Step 5: Solve for x
    x = 202,341.11/642.68
  6. Step 6: Final answer
    x = 314.84

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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.