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Finding the Fourth Proportional to 1,188.21, 1,639.43 and 715.72

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Solution

The fourth proportional to 1,188.21, 1,639.43 and 715.72 is: 987.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.21 : 1,639.43 = 715.72 : x
  2. Step 2: Convert to fraction form
    1,188.21/1,639.43 = 715.72/x
  3. Step 3: Cross multiply
    1,188.21x = 1,639.43 × 715.72
  4. Step 4: Simplify right side
    1,188.21x = 1,173,372.84
  5. Step 5: Solve for x
    x = 1,173,372.84/1,188.21
  6. Step 6: Final answer
    x = 987.51

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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.