B. s_1 and s_2 are the inscribed and circumscribed circles of a triangle with sides 3, 4, 5, then area of s_1/area of s_2 =
Hint: Answer must be 4/25
Answers
Answer:
first you mark me as brain list
Given :-
S₁ and S₂ are the inscribed and circumscribed circles of a triangle.
Length of sides of the triangle are 3, 4 and 5 units.
To find :-
(area of S₁ ) /( area of S₂)
Concept and formula used :-
Let ABC be a triangle of length AB = c units , BC = a units and AC = b units. [ Refer fig-a ]
1. Radius of inscribed circle = (Area of triangle) / (semi perimeter of triangle )
2. Area of triangle = 1/2 × base × height
3. Semi perimeter of triangle = (Sum of all sides of triangle)/2
4. Circumradius = a/2sinA = b/2SinB = c/2SinC
or
Circumradius = (abc)/(4× area of triangle)
5. Area of circle = π × r²
Solution :-
Let's consider a triangle EFG of length 3, 4 and 5 units.
Now, we can observe that :-
=> 3²+ 4² = 5²
=> 9+16 = 25
=> 25 = 25
Triangle EFG is a right angle triangle because it's sides are forming Pythagoras triplet. [ Refer fig-b ]
→ Radius of inscribed circle = (Area of triangle) / (semi perimeter of triangle )
➡️Area of triangle EFG = (1/2) × 3 × 4
➡️Area of triangle EFG = 12/2 square units
⏩semi perimeter of triangle EFG = (3+4+5)/2
⏩semi perimeter of triangle EFG = 12/2 units
→ Radius of inscribed circle = (12/2 ) / (12/2) = 1 unit
Area of inscribed circle (S₁ )= π×1² = π square units ...(1)
→ Circumradius = GF/2sinE
Now, ∠E = 90° and GF = 5 units
→ Circumradius = 5/(2× Sin90°)
→ 5/2 units
Area of circumscribed circle (S₂)= π × (5/2)² = (25π)/(4) square units ...(2)
From (1) and (2) :-
➡️(area of S₁ ) /( area of S₂) = π /[(25π)/(4)]
➡️π × (4/25π)
➡️1 × 4/25
➡️ 4/25
- Answer : 4/25