Question 1206348
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The side which is the diameter is 10 = 5*2 cm long.


Two other sides form a right angle, since they lean on the diameter.


So, we have a right-angled triangle with the hypotenuse of 10 cm
and one leg is 2 cm longer than another.


Hence, as probably you just can to guess, this triangle is (3,4,5)-triangle 
with the sides 6 cm, 8 cm and 10 cm.


Its perimeter is  6+8+10 = 24 cm.

Its area is {{{(1/2)*6*8}}} = 3*8 = 24 cm^2.
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Solved.