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Finding the Fourth Proportional to 644.42, 889.17 and 378.78

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Solution

The fourth proportional to 644.42, 889.17 and 378.78 is: 522.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.42 : 889.17 = 378.78 : x
  2. Step 2: Convert to fraction form
    644.42/889.17 = 378.78/x
  3. Step 3: Cross multiply
    644.42x = 889.17 × 378.78
  4. Step 4: Simplify right side
    644.42x = 336,799.81
  5. Step 5: Solve for x
    x = 336,799.81/644.42
  6. Step 6: Final answer
    x = 522.64

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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.