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Finding the Third Proportional to 390.45 and 703.69

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Solution

The third proportional to 390.45 and 703.69 is: 1,268.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.45 : 703.69 = 703.69 : x
  2. Step 2: Convert to fraction form
    390.45/703.69 = 703.69/x
  3. Step 3: Cross multiply
    390.45x = 703.69 × 703.69
  4. Step 4: Simplify right side
    390.45x = 495,176.10
  5. Step 5: Solve for x
    x = 495,176.10/390.45
  6. Step 6: Final answer
    x = 1,268.23

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Why These Related Problems?

These problems maintain the same ratio (1.80) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.