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Finding the Fourth Proportional to 621.64, 857.84 and 388.76

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Solution

The fourth proportional to 621.64, 857.84 and 388.76 is: 536.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.64 : 857.84 = 388.76 : x
  2. Step 2: Convert to fraction form
    621.64/857.84 = 388.76/x
  3. Step 3: Cross multiply
    621.64x = 857.84 × 388.76
  4. Step 4: Simplify right side
    621.64x = 333,493.88
  5. Step 5: Solve for x
    x = 333,493.88/621.64
  6. Step 6: Final answer
    x = 536.47

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Double scale
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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.