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Finding the Fourth Proportional to 919.21, 1,268.51 and 499.57

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Solution

The fourth proportional to 919.21, 1,268.51 and 499.57 is: 689.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.21 : 1,268.51 = 499.57 : x
  2. Step 2: Convert to fraction form
    919.21/1,268.51 = 499.57/x
  3. Step 3: Cross multiply
    919.21x = 1,268.51 × 499.57
  4. Step 4: Simplify right side
    919.21x = 633,703.20
  5. Step 5: Solve for x
    x = 633,703.20/919.21
  6. Step 6: Final answer
    x = 689.40

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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.