Home / 225-420

Finding the Third Proportional to 225 and 420

Calculator

Solution

The third proportional to 225 and 420 is: 784

Step by Step Solution

  1. Step 1: Write the proportion equation
    225 : 420 = 420 : x
  2. Step 2: Convert to fraction form
    225/420 = 420/x
  3. Step 3: Cross multiply
    225x = 420 × 420
  4. Step 4: Simplify right side
    225x = 176,400
  5. Step 5: Solve for x
    x = 176,400/225
  6. Step 6: Final answer
    x = 784

Related Problems

Find third proportional to 112.50 and 210
Half scale
Find third proportional to 450 and 840
Double scale
Find third proportional to 227 and 424
Similar ratio
Find third proportional to 337.50 and 630
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.87) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.