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Finding the Fourth Proportional to 921.12, 1,270.32 and 621.84

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Solution

The fourth proportional to 921.12, 1,270.32 and 621.84 is: 857.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.12 : 1,270.32 = 621.84 : x
  2. Step 2: Convert to fraction form
    921.12/1,270.32 = 621.84/x
  3. Step 3: Cross multiply
    921.12x = 1,270.32 × 621.84
  4. Step 4: Simplify right side
    921.12x = 789,935.79
  5. Step 5: Solve for x
    x = 789,935.79/921.12
  6. Step 6: Final answer
    x = 857.58

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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.