Home / 405-900

Finding the Third Proportional to 405 and 900

Calculator

Solution

The third proportional to 405 and 900 is: 2,000

Step by Step Solution

  1. Step 1: Write the proportion equation
    405 : 900 = 900 : x
  2. Step 2: Convert to fraction form
    405/900 = 900/x
  3. Step 3: Cross multiply
    405x = 900 × 900
  4. Step 4: Simplify right side
    405x = 810,000
  5. Step 5: Solve for x
    x = 810,000/405
  6. Step 6: Final answer
    x = 2,000

Related Problems

Find third proportional to 202.50 and 450
Half scale
Find third proportional to 810 and 1,800
Double scale
Find third proportional to 407 and 904
Similar ratio
Find third proportional to 607.50 and 1,350
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.