Explanation:
sorry I can only explain as there are no labels to each diagram
The first diagram is single and can solved using triangular formular given as 1/2 ×base × height
A = 1/2 × 5 × 12
A = 30cm^2..
as for the second one...it consist of 2 diagrams which will be solved separately before adding ...it can simply be done using Pythagoras theorem..
To get the smaller part ...out tita is 45degrees while our adjacent is 4 and opposite is x we are to find x which is the height...
using SOH CAH TOA...
WE HAVE TAN45= opp/adj
Tan45= x/ 4
Tan 45 =1 ...so
1 = x/ 4
and x= 4 ...
so...having our height as 4 and base as 4 ..
Area of smaller triangle become 1/2 × 4 × 4
A = 8cm^2 ...
......SOLVING FOR THE SECOND DIAGRAM ..
WE HAVE the height as ( dotted spot + undotted spot ) = 4 + 4 = 8cm
and our base can be gotten from
Tan45 = opp / adj
1 = 8/x ..
x = 8cm ....so the base is 8 and the height is 8
..
The Area becomes 1/2 × 8×8 = 32cm ...
Total area becomes 32cm + 8cm = 40cm^2