Home / 857.65-1,286.47-208.38

Finding the Fourth Proportional to 857.65, 1,286.47 and 208.38

Calculator

Solution

The fourth proportional to 857.65, 1,286.47 and 208.38 is: 312.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.65 : 1,286.47 = 208.38 : x
  2. Step 2: Convert to fraction form
    857.65/1,286.47 = 208.38/x
  3. Step 3: Cross multiply
    857.65x = 1,286.47 × 208.38
  4. Step 4: Simplify right side
    857.65x = 268,069.66
  5. Step 5: Solve for x
    x = 268,069.66/857.65
  6. Step 6: Final answer
    x = 312.56

Related Problems

Find fourth proportional to 428.82, 643.23 and 104.19
Half scale
Find fourth proportional to 1,715.29, 2,572.94 and 416.75
Double scale
Find fourth proportional to 858.65, 1,287.97 and 209.38
Similar ratio
Find fourth proportional to 1,286.47, 1,929.70 and 312.56
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.