Home / 840-1,278

Finding the Third Proportional to 840 and 1,278

Calculator

Solution

The third proportional to 840 and 1,278 is: 1,944.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    840 : 1,278 = 1,278 : x
  2. Step 2: Convert to fraction form
    840/1,278 = 1,278/x
  3. Step 3: Cross multiply
    840x = 1,278 × 1,278
  4. Step 4: Simplify right side
    840x = 1,633,284
  5. Step 5: Solve for x
    x = 1,633,284/840
  6. Step 6: Final answer
    x = 1,944.39

Related Problems

Find third proportional to 420 and 639
Half scale
Find third proportional to 1,680 and 2,556
Double scale
Find third proportional to 842 and 1,281
Similar ratio
Find third proportional to 1,260 and 1,917
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.