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Finding the Fourth Proportional to 987.16, 1,361.32 and 788.64

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Solution

The fourth proportional to 987.16, 1,361.32 and 788.64 is: 1,087.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.16 : 1,361.32 = 788.64 : x
  2. Step 2: Convert to fraction form
    987.16/1,361.32 = 788.64/x
  3. Step 3: Cross multiply
    987.16x = 1,361.32 × 788.64
  4. Step 4: Simplify right side
    987.16x = 1,073,591.40
  5. Step 5: Solve for x
    x = 1,073,591.40/987.16
  6. Step 6: Final answer
    x = 1,087.56

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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.