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Finding the Fourth Proportional to 642.51, 964.13 and 257.79

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Solution

The fourth proportional to 642.51, 964.13 and 257.79 is: 386.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.51 : 964.13 = 257.79 : x
  2. Step 2: Convert to fraction form
    642.51/964.13 = 257.79/x
  3. Step 3: Cross multiply
    642.51x = 964.13 × 257.79
  4. Step 4: Simplify right side
    642.51x = 248,543.07
  5. Step 5: Solve for x
    x = 248,543.07/642.51
  6. Step 6: Final answer
    x = 386.83

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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.