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Finding the Fourth Proportional to 970.24, 1,339.20 and 620.80

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Solution

The fourth proportional to 970.24, 1,339.20 and 620.80 is: 856.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.24 : 1,339.20 = 620.80 : x
  2. Step 2: Convert to fraction form
    970.24/1,339.20 = 620.80/x
  3. Step 3: Cross multiply
    970.24x = 1,339.20 × 620.80
  4. Step 4: Simplify right side
    970.24x = 831,375.36
  5. Step 5: Solve for x
    x = 831,375.36/970.24
  6. Step 6: Final answer
    x = 856.88

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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.