Home / 1,638.90-2,469.29-1,420.20

Finding the Fourth Proportional to 1,638.90, 2,469.29 and 1,420.20

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Solution

The fourth proportional to 1,638.90, 2,469.29 and 1,420.20 is: 2,139.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,638.90 : 2,469.29 = 1,420.20 : x
  2. Step 2: Convert to fraction form
    1,638.90/2,469.29 = 1,420.20/x
  3. Step 3: Cross multiply
    1,638.90x = 2,469.29 × 1,420.20
  4. Step 4: Simplify right side
    1,638.90x = 3,506,878.56
  5. Step 5: Solve for x
    x = 3,506,878.56/1,638.90
  6. Step 6: Final answer
    x = 2,139.78

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.