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Finding the Fourth Proportional to 879.68, 1,316.28 and 781.40

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Solution

The fourth proportional to 879.68, 1,316.28 and 781.40 is: 1,169.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.68 : 1,316.28 = 781.40 : x
  2. Step 2: Convert to fraction form
    879.68/1,316.28 = 781.40/x
  3. Step 3: Cross multiply
    879.68x = 1,316.28 × 781.40
  4. Step 4: Simplify right side
    879.68x = 1,028,541.19
  5. Step 5: Solve for x
    x = 1,028,541.19/879.68
  6. Step 6: Final answer
    x = 1,169.22

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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.