One way to solve this question is through trigonometry. :)
If you've learnt trigonometry, here are the basic formulas:
SOH CAH TOA (These formulas only apply for right-angled triangles)
Sin(angle) = (Side that is Opposite of angle)/(Hypotenuse)
Cos(angle) = (Side that is Adjacent of angle)/(Hypotenuse)
Tan(angle) = (Side that is Opposite of angle)/(Side that is Adjacent of angle)
In this case, we should use sine of b (the angle at the top of triangle as indicated in your question), where the opposite side is the base (I.e. 4 indicated in your question) and the hypotenuse is 9.
sin(b) = 4/9
{Make angle b the subject of the equation}

{Type this into the calculator}
Angle b = 26.4° (rounded off to 1 decimal place)
Hope this helps! :)
use the term blocks to make your addition problem
Answer:
5/6
Step-by-step explanation:
1/6 + 2/3
We need to get a common denominator of 6
1/6 + 2/3 *2/2
1/6 + 4/6
5/6