Home / 255-309

Finding the Third Proportional to 255 and 309

Calculator

Solution

The third proportional to 255 and 309 is: 374.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    255 : 309 = 309 : x
  2. Step 2: Convert to fraction form
    255/309 = 309/x
  3. Step 3: Cross multiply
    255x = 309 × 309
  4. Step 4: Simplify right side
    255x = 95,481
  5. Step 5: Solve for x
    x = 95,481/255
  6. Step 6: Final answer
    x = 374.44

Related Problems

Find third proportional to 127.50 and 154.50
Half scale
Find third proportional to 510 and 618
Double scale
Find third proportional to 257 and 311
Similar ratio
Find third proportional to 382.50 and 463.50
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.