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Finding the Fourth Proportional to 1,187.50, 1,638.75 and 663.67

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Solution

The fourth proportional to 1,187.50, 1,638.75 and 663.67 is: 915.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.50 : 1,638.75 = 663.67 : x
  2. Step 2: Convert to fraction form
    1,187.50/1,638.75 = 663.67/x
  3. Step 3: Cross multiply
    1,187.50x = 1,638.75 × 663.67
  4. Step 4: Simplify right side
    1,187.50x = 1,087,589.21
  5. Step 5: Solve for x
    x = 1,087,589.21/1,187.50
  6. Step 6: Final answer
    x = 915.86

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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.