Home / 305-398.75

Finding the Third Proportional to 305 and 398.75

Calculator

Solution

The third proportional to 305 and 398.75 is: 521.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    305 : 398.75 = 398.75 : x
  2. Step 2: Convert to fraction form
    305/398.75 = 398.75/x
  3. Step 3: Cross multiply
    305x = 398.75 × 398.75
  4. Step 4: Simplify right side
    305x = 159,001.56
  5. Step 5: Solve for x
    x = 159,001.56/305
  6. Step 6: Final answer
    x = 521.32

Related Problems

Find third proportional to 152.50 and 199.38
Half scale
Find third proportional to 610 and 797.50
Double scale
Find third proportional to 307 and 401
Similar ratio
Find third proportional to 457.50 and 598.13
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.