Question

a right angled triangle PQR where angle of Q is 90° is rotated about QR and PQ.if QR=16cm and PR=20cm ,compare the curve surface areas of the right circulat cones so formed by the triangle.

Answer 1

first draw 16cm a straight line as a base. then name it as a Q and R. Then take measurement of 90 degree from Q and draw a straight line. Then from point R take 20cm length and cut an arc on line QP by using compass then join the line from the arc to point R