Home / 480-639

Finding the Third Proportional to 480 and 639

Calculator

Solution

The third proportional to 480 and 639 is: 850.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    480 : 639 = 639 : x
  2. Step 2: Convert to fraction form
    480/639 = 639/x
  3. Step 3: Cross multiply
    480x = 639 × 639
  4. Step 4: Simplify right side
    480x = 408,321
  5. Step 5: Solve for x
    x = 408,321/480
  6. Step 6: Final answer
    x = 850.67

Related Problems

Find third proportional to 240 and 319.50
Half scale
Find third proportional to 960 and 1,278
Double scale
Find third proportional to 482 and 642
Similar ratio
Find third proportional to 720 and 958.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.