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Finding the Fourth Proportional to 970.68, 1,339.98 and 639.12

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Solution

The fourth proportional to 970.68, 1,339.98 and 639.12 is: 882.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.68 : 1,339.98 = 639.12 : x
  2. Step 2: Convert to fraction form
    970.68/1,339.98 = 639.12/x
  3. Step 3: Cross multiply
    970.68x = 1,339.98 × 639.12
  4. Step 4: Simplify right side
    970.68x = 856,408.02
  5. Step 5: Solve for x
    x = 856,408.02/970.68
  6. Step 6: Final answer
    x = 882.28

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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.