SOLUTION: 3 circle, radii of centre PQR are 3.5 cm, x cm, 7 cm. Given that angle of PQR = 90 degree. a. show that {{{2x^2+21x-49=0}}} b. find x

Algebra.Com
Question 704018: 3 circle, radii of centre PQR are 3.5 cm, x cm, 7 cm. Given that angle of PQR = 90 degree.
a. show that
b. find x

Answer by sachi(548)   (Show Source): You can put this solution on YOUR website!
3 circle, radii of centre PQR are 3.5 cm, x cm, 7 cm. Given that angle of PQR = 90 degree.& of course the missing part is they are touching each other
so PQ=3.5+x=7/2*x QR=7+x & PR=7+3.5=7+7/2=21/2
PQR is a right triangle
so PQ^2+QR^2=PR^2
or(7/2+x)^2+(7+x)^2=(21/2)^2=441/4
or 49/4+x^2+7x+49+x^2+14x=441/4
or 2x^2+21x=441/4-49/4-49=49
or 2x^2+21x-49=0 ANS a
now multiplying 8 on both sides
16x^2+168x-392=0
or (4x)^2+2*4x*21+441-441-392=0
or (4x+21)^2=833
or x=(-21+/-sqrt833)/4
ans

RELATED QUESTIONS

please help me solve this question:-ABCD is a rectangle in which AB=(4x+3)cm and... (answered by Earlsdon)
1. In isosceles triangle LKM, with vertex angle K (figure shown below), answer the... (answered by MathLover1)
To whom may it concern, PQR and SQR are both triangles. In fact, SQR located within... (answered by AnlytcPhil,venugopalramana)
The sides of a triangle are 3 cm, 5 cm and 7 cm respectively. Show that the largest angle (answered by Fombitz)
PQRS is a parallelogram with PQ=2x cm, QR=x cm and angle PQR=110°. If the parallelogram... (answered by Theo,ikleyn)
The figure shows a right angled triangle where angle ACB=90°. Given that AB=(2x+1)cm,... (answered by josgarithmetic)
The figure shows a right angled triangle where angle ACB=90°. Given that AB=(2x+1)cm,... (answered by greenestamps)
You will have to go here for the diagram:... (answered by ccs2011)
Two rectangles A and B each have an area of 11 cm^2 The length of rectangle A is x cm... (answered by josmiceli,ikleyn,MathTherapy)