Answer:
x = 8.8 cm
Explanation:
This is a right-angled triangle, and we are given two sides, so we can use pythagoras Theoren

Where 'c' is the hypotenuse (the longest side in right angled triangle and is always opposite to the 90 degree angle).
'a' and 'b' are the other two sides.
So now we have:
2.6^2 + x^2 = 9.2^2 (Solve for 'x')
x^2 = 9.2^2 - 2.6^2
x =

x = 8.8 cm (2 s.f. as other dimensions are also 2 s.f.)