Answer:
C
Explanation:
The diagonals of a square bisect the angles, thus
x = 0.5 × 90° = 45°
The sides of a square are congruent.
Using the sine ratio on the right triangle on the left and the exact value
sin45° =
, then
sin45° =
=

Multiply both sides by y
y × sin45° = 10.9, that is
y ×
= 10.9
Multiply both sides by

y = 10.9
