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Finding the Fourth Proportional to 642.21, 962.70 and 209.07

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Solution

The fourth proportional to 642.21, 962.70 and 209.07 is: 313.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.21 : 962.70 = 209.07 : x
  2. Step 2: Convert to fraction form
    642.21/962.70 = 209.07/x
  3. Step 3: Cross multiply
    642.21x = 962.70 × 209.07
  4. Step 4: Simplify right side
    642.21x = 201,271.69
  5. Step 5: Solve for x
    x = 201,271.69/642.21
  6. Step 6: Final answer
    x = 313.40

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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.