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Finding the Fourth Proportional to 998.72, 1,378.44 and 644.39

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Solution

The fourth proportional to 998.72, 1,378.44 and 644.39 is: 889.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.72 : 1,378.44 = 644.39 : x
  2. Step 2: Convert to fraction form
    998.72/1,378.44 = 644.39/x
  3. Step 3: Cross multiply
    998.72x = 1,378.44 × 644.39
  4. Step 4: Simplify right side
    998.72x = 888,246.06
  5. Step 5: Solve for x
    x = 888,246.06/998.72
  6. Step 6: Final answer
    x = 889.39

Related Problems

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Half scale
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Double scale
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Similar ratio
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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.