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Finding the Fourth Proportional to 669.12, 923.20 and 393.12

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Solution

The fourth proportional to 669.12, 923.20 and 393.12 is: 542.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.12 : 923.20 = 393.12 : x
  2. Step 2: Convert to fraction form
    669.12/923.20 = 393.12/x
  3. Step 3: Cross multiply
    669.12x = 923.20 × 393.12
  4. Step 4: Simplify right side
    669.12x = 362,928.38
  5. Step 5: Solve for x
    x = 362,928.38/669.12
  6. Step 6: Final answer
    x = 542.40

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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.