Home / 1,638.40-2,261.20-939.76

Finding the Fourth Proportional to 1,638.40, 2,261.20 and 939.76

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Solution

The fourth proportional to 1,638.40, 2,261.20 and 939.76 is: 1,296.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,638.40 : 2,261.20 = 939.76 : x
  2. Step 2: Convert to fraction form
    1,638.40/2,261.20 = 939.76/x
  3. Step 3: Cross multiply
    1,638.40x = 2,261.20 × 939.76
  4. Step 4: Simplify right side
    1,638.40x = 2,124,985.31
  5. Step 5: Solve for x
    x = 2,124,985.31/1,638.40
  6. Step 6: Final answer
    x = 1,296.99

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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.