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Finding the Fourth Proportional to 1,221.12, 1,685.16 and 669.12

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Solution

The fourth proportional to 1,221.12, 1,685.16 and 669.12 is: 923.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.12 : 1,685.16 = 669.12 : x
  2. Step 2: Convert to fraction form
    1,221.12/1,685.16 = 669.12/x
  3. Step 3: Cross multiply
    1,221.12x = 1,685.16 × 669.12
  4. Step 4: Simplify right side
    1,221.12x = 1,127,574.26
  5. Step 5: Solve for x
    x = 1,127,574.26/1,221.12
  6. Step 6: Final answer
    x = 923.39

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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.