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Finding the Fourth Proportional to 1,038.30, 1,431.91 and 688.38

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Solution

The fourth proportional to 1,038.30, 1,431.91 and 688.38 is: 949.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,038.30 : 1,431.91 = 688.38 : x
  2. Step 2: Convert to fraction form
    1,038.30/1,431.91 = 688.38/x
  3. Step 3: Cross multiply
    1,038.30x = 1,431.91 × 688.38
  4. Step 4: Simplify right side
    1,038.30x = 985,698.21
  5. Step 5: Solve for x
    x = 985,698.21/1,038.30
  6. Step 6: Final answer
    x = 949.34

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1.5x scale

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.