Home / 199.80-299.75-78.12

Finding the Fourth Proportional to 199.80, 299.75 and 78.12

Calculator

Solution

The fourth proportional to 199.80, 299.75 and 78.12 is: 117.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.80 : 299.75 = 78.12 : x
  2. Step 2: Convert to fraction form
    199.80/299.75 = 78.12/x
  3. Step 3: Cross multiply
    199.80x = 299.75 × 78.12
  4. Step 4: Simplify right side
    199.80x = 23,416.08
  5. Step 5: Solve for x
    x = 23,416.08/199.80
  6. Step 6: Final answer
    x = 117.20

Related Problems

Find fourth proportional to 99.90, 149.87 and 39.06
Half scale
Find fourth proportional to 399.60, 599.49 and 156.24
Double scale
Find fourth proportional to 200.80, 301.25 and 79.12
Similar ratio
Find fourth proportional to 299.70, 449.62 and 117.18
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.