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Finding the Fourth Proportional to 1,089.72, 1,502.79 and 840.64

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Solution

The fourth proportional to 1,089.72, 1,502.79 and 840.64 is: 1,159.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,089.72 : 1,502.79 = 840.64 : x
  2. Step 2: Convert to fraction form
    1,089.72/1,502.79 = 840.64/x
  3. Step 3: Cross multiply
    1,089.72x = 1,502.79 × 840.64
  4. Step 4: Simplify right side
    1,089.72x = 1,263,305.39
  5. Step 5: Solve for x
    x = 1,263,305.39/1,089.72
  6. Step 6: Final answer
    x = 1,159.29

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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.