Unsure what you mean by diagonal right triangle
but if you wanted to find the hypothenuse (longest side) of a right triangle, you can apply pythagorean theorem

where c is the hypothenuse
a and b are the other sides
Answer:
<A = 26°
Step-by-step explanation:
4x - 30 + 4x - 14 = 180
Supplementary angles sum together to make 180
=> 4x + 4x = 16x
=> -30-14 = -44
16x = 180+44
16x = 224
x = 224/16
x = 14°
4(14) - 30 = 26°