Properties of Triangles 3 Question 5

5. In a ABC, let C=π/2. If r is the inradius and R is the circumradius of the triangle, then 2(r+R) is equal to

(2000,2M)

(a) a+b

(b) b+c

(c) c+a

(d) a+b+c

Passage Based Problems

Consider the circle x2+y2=9 and the parabola y2=8x. They intersect at P and Q in the first and the fourth quadrants, respectively. Tangents to the circle at P and Q intersect the X-axis at R and tangents to the parabola at P and Q intersect the X-axis at S.

(2007,8M)

Show Answer

Answer:

Correct Answer: 5. (a)

Solution:

  1. Here, R2=MC2=14(a2+b2) [by distance from origin] =14c2 [by Pythagoras theorem]

R=c2

Next, r=(sc)tan(C/2)=(sc)tanπ/4=sc

2(r+R)=2r+2R=2s2c+c

=a+b+cc=a+b



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक