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Finding the Fourth Proportional to 1,189.21, 1,641.09 and 685.15

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Solution

The fourth proportional to 1,189.21, 1,641.09 and 685.15 is: 945.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.21 : 1,641.09 = 685.15 : x
  2. Step 2: Convert to fraction form
    1,189.21/1,641.09 = 685.15/x
  3. Step 3: Cross multiply
    1,189.21x = 1,641.09 × 685.15
  4. Step 4: Simplify right side
    1,189.21x = 1,124,392.81
  5. Step 5: Solve for x
    x = 1,124,392.81/1,189.21
  6. Step 6: Final answer
    x = 945.50

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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.