Home / 405-621

Finding the Third Proportional to 405 and 621

Calculator

Solution

The third proportional to 405 and 621 is: 952.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    405 : 621 = 621 : x
  2. Step 2: Convert to fraction form
    405/621 = 621/x
  3. Step 3: Cross multiply
    405x = 621 × 621
  4. Step 4: Simplify right side
    405x = 385,641
  5. Step 5: Solve for x
    x = 385,641/405
  6. Step 6: Final answer
    x = 952.20

Related Problems

Find third proportional to 202.50 and 310.50
Half scale
Find third proportional to 810 and 1,242
Double scale
Find third proportional to 407 and 624
Similar ratio
Find third proportional to 607.50 and 931.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.53) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.