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Finding the Fourth Proportional to 838.68, 1,253.20 and 639.92

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Solution

The fourth proportional to 838.68, 1,253.20 and 639.92 is: 956.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.68 : 1,253.20 = 639.92 : x
  2. Step 2: Convert to fraction form
    838.68/1,253.20 = 639.92/x
  3. Step 3: Cross multiply
    838.68x = 1,253.20 × 639.92
  4. Step 4: Simplify right side
    838.68x = 801,947.74
  5. Step 5: Solve for x
    x = 801,947.74/838.68
  6. Step 6: Final answer
    x = 956.20

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.