im very confused on finding y

Answer:
In this case, you can use the concept of cosine to calculate y, and things are even easier when you have one of the special angles which is a 45° angle.
So we know that: cos45° = √2/2
This fact will always be true. In our case, we have:
cos45° = 7/y
Therefore, we have the equation:
7/y = √2/2
⇔ 14 = y√2
⇔ y = 14/√2
⇔ y = √196/√2 = √(196/2) = √98 = 7√2
So y is equal to 7√2
Answer:
7√2
Step-by-step explanation:
By observation, we can determine that because this is a right angle triangle with one of the internal angles = 45°, that the remaining unknown angle is also 45°, which makes this an isosceles triangle.
This means that x = 7
we can find y by using the Pythagorean equation:
y² = x² + 7²
y² = 7² + 7²
y² = 98
y = √98 = 7√2