Home / 378.42-642.30

Finding the Third Proportional to 378.42 and 642.30

Calculator

Solution

The third proportional to 378.42 and 642.30 is: 1,090.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.42 : 642.30 = 642.30 : x
  2. Step 2: Convert to fraction form
    378.42/642.30 = 642.30/x
  3. Step 3: Cross multiply
    378.42x = 642.30 × 642.30
  4. Step 4: Simplify right side
    378.42x = 412,555.31
  5. Step 5: Solve for x
    x = 412,555.31/378.42
  6. Step 6: Final answer
    x = 1,090.20

Related Problems

Find third proportional to 189.21 and 321.15
Half scale
Find third proportional to 756.84 and 1,284.61
Double scale
Find third proportional to 380 and 646
Similar ratio
Find third proportional to 567.63 and 963.46
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.70) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.