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How many Triangles can make in 24 centimetre square |
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Answer» Answer: Let a=8 cm , b =6 cm and ANGLE between sides a and b is C. Area of triangle ABC = 1/2.a.b.sinC. 1/2.8 cm.6 cm.sinC = 12 cm^2 24 cm^2.sinC=12 cm^2 sinC= 12cm^2/24 cm^2= 1/2 C= 30° ,150° are only possible (as sum of all interior angles is 180°). Thus, only two TRIANGLES are possible in which in 1st triangle angle between given sides is 30° and in 2nd triangle angle between sides is 150°. , Answer. Second method:- Let third side is x cm long. a= 8 cm , b = 6 cm and c = x cm. s=(a+b+c)/2=(8+6+x)/2= 7+(x/2). Area of triangle =[s (s-a) (s-b) (s-c)]^1/2 12 =[{7+(x/2)}.{x/2–1}.{x/2+1}.{7-x/2}]^1/2 12 =[{49-x^2/4}.{x^2/4–1}]^1/2 On squaring both sides 144 =49x^2/4–49-x^4/16+x^/4 193 =50x^2/4-x^4/16 x^4/16–50x^2/4+193 =0 (x^2/4)^2–2×(x^2/4)×25+(25)^2–625+193=0 (x^2/4 -25)^2= 432. (x^2/4-25)= +/-12.(3^1/2) = +/-20.784 x^2/4 = 25 +/-20.784 x^2/4= 45.784 , 4.216 x^2= 183.136 , 16.864 x= 13.53 cm , 4.11 cm. Hare both the length of 3RD side are possible to construct the triangle, so that two triangles are possible. , Answer. |
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