Here is the complete question
The internal shear force V at a certain section of a steel beam is 80 kN, and the moment of inertia is 64,900,000 . Determine the horizontal shear stress at point H, which is located L  = 20 mm below the centriod
The missing image which is the remaining part of this question is attached in the image below.
Answer:
The horizontal shear stress at point H is  
Explanation:
Given that :
The internal shear force V  =  80 kN = 80 × 10³ N
The moment of inertia = 64,900,000
The length = 20 mm below the centriod
The horizontal shear stress  
 can be calculated by using the equation:

where;
Q = moment of area above or below the point H
b = thickness of the beam = 10  mm
From the centroid ; 
Q = 
Q = 
  
Q = ( ( 70 × 10) × (55) + ( 210 × 15) (90 + 15/2) ) mm³
Q = ( ( 700) × (55) + ( 3150 ) ( 97.5)  ) mm³
Q = ( 38500 +  307125 ) mm³
Q = 345625 mm³





 The horizontal shear stress at point H is  