Question

X and Y are centres of circles of radius 9 cm and 2 cm and XY = 17 cm . Z is the centre of radius r cm, which touches the above circles externally. Given that angle XYZ = 90 degree, write an equation in r and solve it for r.

Answer 1

answer may be this

theorem applied is PYTHAGORUS THEORM
obtained equation :
$( {r + 9})^{2} ={17}^{2} + ({r + 2)}^{2}$
$obtined \: that \: r = 283 \div 22 = 12.8636363637$