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Finding the Fourth Proportional to 998.90, 1,378.49 and 556.81

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Solution

The fourth proportional to 998.90, 1,378.49 and 556.81 is: 768.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.90 : 1,378.49 = 556.81 : x
  2. Step 2: Convert to fraction form
    998.90/1,378.49 = 556.81/x
  3. Step 3: Cross multiply
    998.90x = 1,378.49 × 556.81
  4. Step 4: Simplify right side
    998.90x = 767,550.79
  5. Step 5: Solve for x
    x = 767,550.79/998.90
  6. Step 6: Final answer
    x = 768.40

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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.