We can solve for the 3 triangle sides.
The left side is easy 6.
Second side² = 7² + 4²
Second side² = 49 + 16
Second side = square root (65)
Second side = 8.0622577483
Third Side² = 7² + 2²
Third Side² = 53
Third Side = 7.2801098893
When we know 3 sides, we use Heron's formula for calculating area:
Perimeter = 21.3423676376
Semi-Perimeter = 10.6711838188
Using Heron's Formula
area = square root (10.6711838188 * 4.6711838188 * 2.6089260705 * 3.3910739295 )
area = square root (441)
area = 21
Yes, it's just that "easy". LOL