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Finding the Fourth Proportional to 1,221.49, 1,685.41 and 724.20

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Solution

The fourth proportional to 1,221.49, 1,685.41 and 724.20 is: 999.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.49 : 1,685.41 = 724.20 : x
  2. Step 2: Convert to fraction form
    1,221.49/1,685.41 = 724.20/x
  3. Step 3: Cross multiply
    1,221.49x = 1,685.41 × 724.20
  4. Step 4: Simplify right side
    1,221.49x = 1,220,573.92
  5. Step 5: Solve for x
    x = 1,220,573.92/1,221.49
  6. Step 6: Final answer
    x = 999.25

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1.5x scale

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.