Answer:
Area 36 square units; formula area = 1/2 x base x height
Step-by-step explanation:
Area = 1/2 x base x height
You're not given the base or the height, but this is an isosceles rt. triangle and the base and height are both opposite equal angles (45 degrees) so those two sides are equal to each other, too.
Lets say the base length is b. That is the height length too, then
From Pythagoras, we have
b² + b² = 12², so 2b² = 12² = 144.
So b² = 72.
So base = √72. But the height is the same length, so height = √72.
So area = 1/2 x base x height = 1/2 x √72 x √72 = 1/2 x 72 = 36 square units
