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Finding the Fourth Proportional to 1,221.40, 1,685.37 and 724.06

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Solution

The fourth proportional to 1,221.40, 1,685.37 and 724.06 is: 999.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.40 : 1,685.37 = 724.06 : x
  2. Step 2: Convert to fraction form
    1,221.40/1,685.37 = 724.06/x
  3. Step 3: Cross multiply
    1,221.40x = 1,685.37 × 724.06
  4. Step 4: Simplify right side
    1,221.40x = 1,220,309.00
  5. Step 5: Solve for x
    x = 1,220,309.00/1,221.40
  6. Step 6: Final answer
    x = 999.11

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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.