Home / 1,205-1,405

Finding the Third Proportional to 1,205 and 1,405

Calculator

Solution

The third proportional to 1,205 and 1,405 is: 1,638.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,205 : 1,405 = 1,405 : x
  2. Step 2: Convert to fraction form
    1,205/1,405 = 1,405/x
  3. Step 3: Cross multiply
    1,205x = 1,405 × 1,405
  4. Step 4: Simplify right side
    1,205x = 1,974,025
  5. Step 5: Solve for x
    x = 1,974,025/1,205
  6. Step 6: Final answer
    x = 1,638.20

Related Problems

Find third proportional to 602.50 and 702.50
Half scale
Find third proportional to 2,410 and 2,810
Double scale
Find third proportional to 1,207 and 1,407
Similar ratio
Find third proportional to 1,807.50 and 2,107.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.17) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.