Home / 639-1,605

Finding the Third Proportional to 639 and 1,605

Calculator

Solution

The third proportional to 639 and 1,605 is: 4,031.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    639 : 1,605 = 1,605 : x
  2. Step 2: Convert to fraction form
    639/1,605 = 1,605/x
  3. Step 3: Cross multiply
    639x = 1,605 × 1,605
  4. Step 4: Simplify right side
    639x = 2,576,025
  5. Step 5: Solve for x
    x = 2,576,025/639
  6. Step 6: Final answer
    x = 4,031.34

Related Problems

Find third proportional to 319.50 and 802.50
Half scale
Find third proportional to 1,278 and 3,210
Double scale
Find third proportional to 641 and 1,610
Similar ratio
Find third proportional to 958.50 and 2,407.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.