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Finding the Fourth Proportional to 1,138.60, 1,570.78 and 718.74

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Solution

The fourth proportional to 1,138.60, 1,570.78 and 718.74 is: 991.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.60 : 1,570.78 = 718.74 : x
  2. Step 2: Convert to fraction form
    1,138.60/1,570.78 = 718.74/x
  3. Step 3: Cross multiply
    1,138.60x = 1,570.78 × 718.74
  4. Step 4: Simplify right side
    1,138.60x = 1,128,982.42
  5. Step 5: Solve for x
    x = 1,128,982.42/1,138.60
  6. Step 6: Final answer
    x = 991.55

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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.