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Finding the Fourth Proportional to 1,105.40, 1,525.20 and 639.38

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Solution

The fourth proportional to 1,105.40, 1,525.20 and 639.38 is: 882.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,105.40 : 1,525.20 = 639.38 : x
  2. Step 2: Convert to fraction form
    1,105.40/1,525.20 = 639.38/x
  3. Step 3: Cross multiply
    1,105.40x = 1,525.20 × 639.38
  4. Step 4: Simplify right side
    1,105.40x = 975,182.38
  5. Step 5: Solve for x
    x = 975,182.38/1,105.40
  6. Step 6: Final answer
    x = 882.20

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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.