Area of complete triangle= 1/2 ×6 ×9 = 27 Sq Unit.
Area of rectangle inside triangle = 2× 5 = 10 sq unit.
area of the gray part of the triangle =Area of triangle - Area of rectangle = 27-10 = 17 Sq unit
Gray area = Big triangle area - white
rectangle area
Gray area = 1/2 × 6 × 9 - 2 × 5
Gray area = 3 × 9 - 10
Gray area = 27 - 10
Gray area = 17
