Home / 215-428

Finding the Third Proportional to 215 and 428

Calculator

Solution

The third proportional to 215 and 428 is: 852.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    215 : 428 = 428 : x
  2. Step 2: Convert to fraction form
    215/428 = 428/x
  3. Step 3: Cross multiply
    215x = 428 × 428
  4. Step 4: Simplify right side
    215x = 183,184
  5. Step 5: Solve for x
    x = 183,184/215
  6. Step 6: Final answer
    x = 852.02

Related Problems

Find third proportional to 107.50 and 214
Half scale
Find third proportional to 430 and 856
Double scale
Find third proportional to 217 and 432
Similar ratio
Find third proportional to 322.50 and 642
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.99) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.