Home / 210.20-315.09-65.81

Finding the Fourth Proportional to 210.20, 315.09 and 65.81

Calculator

Solution

The fourth proportional to 210.20, 315.09 and 65.81 is: 98.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.20 : 315.09 = 65.81 : x
  2. Step 2: Convert to fraction form
    210.20/315.09 = 65.81/x
  3. Step 3: Cross multiply
    210.20x = 315.09 × 65.81
  4. Step 4: Simplify right side
    210.20x = 20,736.86
  5. Step 5: Solve for x
    x = 20,736.86/210.20
  6. Step 6: Final answer
    x = 98.66

Related Problems

Find fourth proportional to 105.10, 157.55 and 32.91
Half scale
Find fourth proportional to 420.39, 630.18 and 131.63
Double scale
Find fourth proportional to 211.20, 316.59 and 66.81
Similar ratio
Find fourth proportional to 315.29, 472.64 and 98.72
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.