You either find the gradient or distance and if there are equal, therefore the opp are equal
        
             
        
        
        
You must have been taught postulates and theorems that allow you to prove triangles congruent, such as SSS, SAS, ASA, etc. Look at the given information of a proof, and see how from the given information, using definitions, postulates, and theorems you have already learned, you can show pairs of corresponding sides and angles to be congruent that will fit into the above methods. Then use one of the methods to prove the triangles congruent.
        
             
        
        
        
The area formula of a circle is  × π.
 × π. 
With that being said, we can solve both problems!
Starting with part A: 
-The radius we know is 21cm. From there, we can substitute in our formula with the new value.
 x π
 x π
From there, we can square our radius:
(21 x 21) x π
(441) x π
And finally, we can multiply by pi to get our answer. 
(441) x π
1385.44236023
Which rounded to the nearest tenth is 1385.4. Therefore, the area of the porthole is 1385.4 centimetres. 
The second part can be followed with the same process, hopefully you understand the concept enough to where you're comfortable solving problems like this on your own. Feel free to reach out if you have any further trouble!
<em>Hope this helped! :)</em>
 
        
             
        
        
        
Answer:
Option E.
Step-by-step explanation:
Let the intended length of Rebecca's swimming is = x units
and we assume the length of the pool = l units
Now it is given in the question that " She covers one fifth of her intended distance "
That means distance covered = 
" After swimming six more lengths of the pool she had covered one quarter of her intended distance"
So 


x = 20×(6l) 
x = 120l
Therefore, Rebecca has to complete 120 lengths of the pool.
Option E is the answer.
 
        
             
        
        
        
Answer:
8/15
Step-by-step explanation: