1.the radii r1,r2,r3 of escribed circles of a triangle ABC are in harmonic progression.if its area is 24 sq.cm. and its perimeter is 24 cm,find the lengths of its sides. ans:6,8,10
2.In a triangle ABC,if A:B:C =3:5:4,then a+b+c√2 is equal to------
A.2b
B.2c
C.3b
D.3a
ans:c
3.if in a triangle ABC,a=5,b=4 and cos(A-B)=3132,then
A.c=6
B.sin A=5√716
C.area of triangle ABC=15√74
D.none of these
ans:ABC
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2 Answers
62first Δ/(s-a), Δ/(s-b), Δ/(s-c), are in HP
so s-a, s-b and s-c are in AP
so a, b, c are in AP..
Now solve the first one..
106for 2:
first find angles.
Then fix a side which u will use as reference for calculating the sum (say 'c') and express all sides in terms of 'c'
find the sum using sine rules (or cosine).
Then convert the sum in 'c' to 'b' and 'a' and see which matches
