Properties, Characteristics and proofs: Properties of triangles within a square

Look at the square below.

Is BE equal to CE?

According to the properties of the square, the diagonals intersect each other, therefore, BE is equal to CE

Yes

Look at the square below:

What types of triangles do the diagonals in the square form?

The diagonals of the square intersect each other, so the four triangles are isosceles. Moreover, since the diagonals are perpendicular to each other, the diagonals form four right-angled triangles. Therefore, the correct answers are A+C

Answers (a) and (c) are correct.

Look at the square below:

What is the area of triangle ACD?

$\frac{x^2}{2}$

Look at the square below:

What is the perimeter of triangle ACD?

$2x+\sqrt{2}x$