Home / 212.45-318.76-90.71

Finding the Fourth Proportional to 212.45, 318.76 and 90.71

Calculator

Solution

The fourth proportional to 212.45, 318.76 and 90.71 is: 136.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.45 : 318.76 = 90.71 : x
  2. Step 2: Convert to fraction form
    212.45/318.76 = 90.71/x
  3. Step 3: Cross multiply
    212.45x = 318.76 × 90.71
  4. Step 4: Simplify right side
    212.45x = 28,914.72
  5. Step 5: Solve for x
    x = 28,914.72/212.45
  6. Step 6: Final answer
    x = 136.10

Related Problems

Find fourth proportional to 106.23, 159.38 and 45.36
Half scale
Find fourth proportional to 424.90, 637.52 and 181.42
Double scale
Find fourth proportional to 213.45, 320.26 and 91.71
Similar ratio
Find fourth proportional to 318.68, 478.14 and 136.07
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.