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Finding the Fourth Proportional to 689.28, 951.15 and 378.78

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Solution

The fourth proportional to 689.28, 951.15 and 378.78 is: 522.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.28 : 951.15 = 378.78 : x
  2. Step 2: Convert to fraction form
    689.28/951.15 = 378.78/x
  3. Step 3: Cross multiply
    689.28x = 951.15 × 378.78
  4. Step 4: Simplify right side
    689.28x = 360,276.60
  5. Step 5: Solve for x
    x = 360,276.60/689.28
  6. Step 6: Final answer
    x = 522.69

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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.