Home / 678.38-978

Finding the Third Proportional to 678.38 and 978

Calculator

Solution

The third proportional to 678.38 and 978 is: 1,409.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.38 : 978 = 978 : x
  2. Step 2: Convert to fraction form
    678.38/978 = 978/x
  3. Step 3: Cross multiply
    678.38x = 978 × 978
  4. Step 4: Simplify right side
    678.38x = 956,484
  5. Step 5: Solve for x
    x = 956,484/678.38
  6. Step 6: Final answer
    x = 1,409.96

Related Problems

Find third proportional to 339.19 and 489
Half scale
Find third proportional to 1,356.75 and 1,956
Double scale
Find third proportional to 680 and 981
Similar ratio
Find third proportional to 1,017.56 and 1,467
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.