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Finding the Fourth Proportional to 998.76, 1,378.60 and 812.10

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Solution

The fourth proportional to 998.76, 1,378.60 and 812.10 is: 1,120.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.76 : 1,378.60 = 812.10 : x
  2. Step 2: Convert to fraction form
    998.76/1,378.60 = 812.10/x
  3. Step 3: Cross multiply
    998.76x = 1,378.60 × 812.10
  4. Step 4: Simplify right side
    998.76x = 1,119,561.06
  5. Step 5: Solve for x
    x = 1,119,561.06/998.76
  6. Step 6: Final answer
    x = 1,120.95

Related Problems

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Half scale
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Double scale
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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.