Home / 399-670

Finding the Third Proportional to 399 and 670

Calculator

Solution

The third proportional to 399 and 670 is: 1,125.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    399 : 670 = 670 : x
  2. Step 2: Convert to fraction form
    399/670 = 670/x
  3. Step 3: Cross multiply
    399x = 670 × 670
  4. Step 4: Simplify right side
    399x = 448,900
  5. Step 5: Solve for x
    x = 448,900/399
  6. Step 6: Final answer
    x = 1,125.06

Related Problems

Find third proportional to 199.50 and 335
Half scale
Find third proportional to 798 and 1,340
Double scale
Find third proportional to 401 and 673
Similar ratio
Find third proportional to 598.50 and 1,005
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.68) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.