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Finding the Fourth Proportional to 971.51, 1,340.73 and 639.70

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Solution

The fourth proportional to 971.51, 1,340.73 and 639.70 is: 882.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    971.51 : 1,340.73 = 639.70 : x
  2. Step 2: Convert to fraction form
    971.51/1,340.73 = 639.70/x
  3. Step 3: Cross multiply
    971.51x = 1,340.73 × 639.70
  4. Step 4: Simplify right side
    971.51x = 857,663.88
  5. Step 5: Solve for x
    x = 857,663.88/971.51
  6. Step 6: Final answer
    x = 882.82

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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.