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Finding the Fourth Proportional to 970.72, 1,339.94 and 639.29

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Solution

The fourth proportional to 970.72, 1,339.94 and 639.29 is: 882.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.72 : 1,339.94 = 639.29 : x
  2. Step 2: Convert to fraction form
    970.72/1,339.94 = 639.29/x
  3. Step 3: Cross multiply
    970.72x = 1,339.94 × 639.29
  4. Step 4: Simplify right side
    970.72x = 856,615.19
  5. Step 5: Solve for x
    x = 856,615.19/970.72
  6. Step 6: Final answer
    x = 882.46

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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.