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Let triangle ABC is right triangle right...

Let triangle ABC is right triangle right angled at C such that `A lt B` and `r=8, R=41` .
Q. `"tan"(A)/(2)=`

A

`(1)/(18)`

B

`(1)/(3)`

C

`(1)/(6)`

D

`(1)/(9)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \( \frac{\tan(A)}{2} \) for triangle \( ABC \) which is a right triangle with \( C \) as the right angle. Given that the inradius \( r = 8 \) and the circumradius \( R = 41 \), we can use the relationships between the sides and angles of the triangle. ### Step-by-Step Solution: 1. **Understanding the Triangle Properties**: - In a right triangle, the circumradius \( R \) is given by the formula: \[ R = \frac{c}{2} \] where \( c \) is the hypotenuse. Therefore, we have: \[ c = 2R = 2 \times 41 = 82 \] 2. **Using the Inradius**: - The inradius \( r \) is given by the formula: \[ r = \frac{A}{s} \] where \( A \) is the area of the triangle and \( s \) is the semi-perimeter. The semi-perimeter \( s \) can also be expressed as: \[ s = \frac{a + b + c}{2} \] where \( a \) and \( b \) are the legs of the triangle. 3. **Finding the Semi-Perimeter**: - Since \( r = 8 \): \[ A = r \cdot s \] - The area \( A \) of triangle \( ABC \) can also be expressed as: \[ A = \frac{1}{2}ab \] - Therefore, we have: \[ 8s = \frac{1}{2}ab \] - Substituting \( s \): \[ 8 \cdot \frac{a + b + 82}{2} = \frac{1}{2}ab \] - Simplifying this gives: \[ 8(a + b + 82) = ab \] 4. **Using Pythagorean Theorem**: - From the Pythagorean theorem, we know: \[ a^2 + b^2 = c^2 = 82^2 = 6724 \] 5. **Setting Up the Equations**: - We now have two equations: 1. \( ab = 8(a + b + 82) \) 2. \( a^2 + b^2 = 6724 \) 6. **Solving the System of Equations**: - Let \( s = a + b \) and \( p = ab \). From the first equation, we can express \( p \): \[ p = 8(s + 82) \] - We can also express \( a^2 + b^2 \) in terms of \( s \) and \( p \): \[ a^2 + b^2 = s^2 - 2p \] - Substituting \( p \): \[ s^2 - 2(8(s + 82)) = 6724 \] - Simplifying this gives: \[ s^2 - 16s - 164 = 6724 \] - Rearranging: \[ s^2 - 16s - 6888 = 0 \] 7. **Finding the Roots**: - Using the quadratic formula \( s = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \): \[ s = \frac{16 \pm \sqrt{(-16)^2 - 4 \cdot 1 \cdot (-6888)}}{2 \cdot 1} \] \[ s = \frac{16 \pm \sqrt{256 + 27552}}{2} \] \[ s = \frac{16 \pm \sqrt{27708}}{2} \] 8. **Calculating \( \tan(A) \)**: - Once we find \( a \) and \( b \), we can find \( \tan(A) \) using: \[ \tan(A) = \frac{a}{b} \] - Finally, we need \( \frac{\tan(A)}{2} \). ### Final Calculation: After calculating the values of \( a \) and \( b \), we can substitute them back to find \( \tan(A) \) and then divide by 2 to get \( \frac{\tan(A)}{2} \).
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