Home / 78.19-90

Finding the Third Proportional to 78.19 and 90

Calculator

Solution

The third proportional to 78.19 and 90 is: 103.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.19 : 90 = 90 : x
  2. Step 2: Convert to fraction form
    78.19/90 = 90/x
  3. Step 3: Cross multiply
    78.19x = 90 × 90
  4. Step 4: Simplify right side
    78.19x = 8,100
  5. Step 5: Solve for x
    x = 8,100/78.19
  6. Step 6: Final answer
    x = 103.60

Related Problems

Find third proportional to 39.09 and 45
Half scale
Find third proportional to 156.38 and 180
Double scale
Find third proportional to 80 and 92
Similar ratio
Find third proportional to 117.28 and 135
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.