Answer:
a) The value of x is 15.89 (don't know if I have to round, sorry)
b) The last angle in the triangle is 39 degrees
Explanation:
Here, we see that x is the hypotenuse,
Using SOHCAHTOA,
if we have the 51 degree angle,
then the adjacent is 10 and we can use CAH to find the hypotenuse = x
cos(51) = adjacent/hypotenuse = 10/x
x = 10/cos(51)
x = 15.89
b) since the sum of the angles in any triangle is 180 , we have,
y + 51 + 90 = 180,
y = 180 - 90 - 51
y = 39 degrees