Home / 380-678

Finding the Third Proportional to 380 and 678

Calculator

Solution

The third proportional to 380 and 678 is: 1,209.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    380 : 678 = 678 : x
  2. Step 2: Convert to fraction form
    380/678 = 678/x
  3. Step 3: Cross multiply
    380x = 678 × 678
  4. Step 4: Simplify right side
    380x = 459,684
  5. Step 5: Solve for x
    x = 459,684/380
  6. Step 6: Final answer
    x = 1,209.69

Related Problems

Find third proportional to 190 and 339
Half scale
Find third proportional to 760 and 1,356
Double scale
Find third proportional to 382 and 682
Similar ratio
Find third proportional to 570 and 1,017
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.78) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.