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Finding the Fourth Proportional to 987.76, 1,361.64 and 847.20

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Solution

The fourth proportional to 987.76, 1,361.64 and 847.20 is: 1,167.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.76 : 1,361.64 = 847.20 : x
  2. Step 2: Convert to fraction form
    987.76/1,361.64 = 847.20/x
  3. Step 3: Cross multiply
    987.76x = 1,361.64 × 847.20
  4. Step 4: Simplify right side
    987.76x = 1,153,581.41
  5. Step 5: Solve for x
    x = 1,153,581.41/987.76
  6. Step 6: Final answer
    x = 1,167.88

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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.