Home / 660-990

Finding the Third Proportional to 660 and 990

Calculator

Solution

The third proportional to 660 and 990 is: 1,485

Step by Step Solution

  1. Step 1: Write the proportion equation
    660 : 990 = 990 : x
  2. Step 2: Convert to fraction form
    660/990 = 990/x
  3. Step 3: Cross multiply
    660x = 990 × 990
  4. Step 4: Simplify right side
    660x = 980,100
  5. Step 5: Solve for x
    x = 980,100/660
  6. Step 6: Final answer
    x = 1,485

Related Problems

Find third proportional to 330 and 495
Half scale
Find third proportional to 1,320 and 1,980
Double scale
Find third proportional to 662 and 993
Similar ratio
Find third proportional to 990 and 1,485
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.