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Finding the Fourth Proportional to 1,287.64, 1,928.94 and 636.40

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Solution

The fourth proportional to 1,287.64, 1,928.94 and 636.40 is: 953.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.64 : 1,928.94 = 636.40 : x
  2. Step 2: Convert to fraction form
    1,287.64/1,928.94 = 636.40/x
  3. Step 3: Cross multiply
    1,287.64x = 1,928.94 × 636.40
  4. Step 4: Simplify right side
    1,287.64x = 1,227,577.42
  5. Step 5: Solve for x
    x = 1,227,577.42/1,287.64
  6. Step 6: Final answer
    x = 953.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.