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Finding the Fourth Proportional to 875.70, 1,207.87 and 639.23

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Solution

The fourth proportional to 875.70, 1,207.87 and 639.23 is: 881.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    875.70 : 1,207.87 = 639.23 : x
  2. Step 2: Convert to fraction form
    875.70/1,207.87 = 639.23/x
  3. Step 3: Cross multiply
    875.70x = 1,207.87 × 639.23
  4. Step 4: Simplify right side
    875.70x = 772,108.16
  5. Step 5: Solve for x
    x = 772,108.16/875.70
  6. Step 6: Final answer
    x = 881.70

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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.