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Finding the Fourth Proportional to 875, 1,207.50 and 642.56

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Solution

The fourth proportional to 875, 1,207.50 and 642.56 is: 886.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    875 : 1,207.50 = 642.56 : x
  2. Step 2: Convert to fraction form
    875/1,207.50 = 642.56/x
  3. Step 3: Cross multiply
    875x = 1,207.50 × 642.56
  4. Step 4: Simplify right side
    875x = 775,891.20
  5. Step 5: Solve for x
    x = 775,891.20/875
  6. Step 6: Final answer
    x = 886.73

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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.