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Finding the Fourth Proportional to 900.20, 1,243.96 and 811.64

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Solution

The fourth proportional to 900.20, 1,243.96 and 811.64 is: 1,121.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    900.20 : 1,243.96 = 811.64 : x
  2. Step 2: Convert to fraction form
    900.20/1,243.96 = 811.64/x
  3. Step 3: Cross multiply
    900.20x = 1,243.96 × 811.64
  4. Step 4: Simplify right side
    900.20x = 1,009,647.69
  5. Step 5: Solve for x
    x = 1,009,647.69/900.20
  6. Step 6: Final answer
    x = 1,121.58

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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.