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Finding the Fourth Proportional to 987.60, 1,361.52 and 870.96

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Solution

The fourth proportional to 987.60, 1,361.52 and 870.96 is: 1,200.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.60 : 1,361.52 = 870.96 : x
  2. Step 2: Convert to fraction form
    987.60/1,361.52 = 870.96/x
  3. Step 3: Cross multiply
    987.60x = 1,361.52 × 870.96
  4. Step 4: Simplify right side
    987.60x = 1,185,829.46
  5. Step 5: Solve for x
    x = 1,185,829.46/987.60
  6. Step 6: Final answer
    x = 1,200.72

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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.