Home / 431-521

Finding the Third Proportional to 431 and 521

Calculator

Solution

The third proportional to 431 and 521 is: 629.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    431 : 521 = 521 : x
  2. Step 2: Convert to fraction form
    431/521 = 521/x
  3. Step 3: Cross multiply
    431x = 521 × 521
  4. Step 4: Simplify right side
    431x = 271,441
  5. Step 5: Solve for x
    x = 271,441/431
  6. Step 6: Final answer
    x = 629.79

Related Problems

Find third proportional to 215.50 and 260.50
Half scale
Find third proportional to 862 and 1,042
Double scale
Find third proportional to 433 and 523
Similar ratio
Find third proportional to 646.50 and 781.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.