Home / 256-390

Finding the Third Proportional to 256 and 390

Calculator

Solution

The third proportional to 256 and 390 is: 594.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    256 : 390 = 390 : x
  2. Step 2: Convert to fraction form
    256/390 = 390/x
  3. Step 3: Cross multiply
    256x = 390 × 390
  4. Step 4: Simplify right side
    256x = 152,100
  5. Step 5: Solve for x
    x = 152,100/256
  6. Step 6: Final answer
    x = 594.14

Related Problems

Find third proportional to 128 and 195
Half scale
Find third proportional to 512 and 780
Double scale
Find third proportional to 258 and 393
Similar ratio
Find third proportional to 384 and 585
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.