Question

how much area of triangle will increase in percentage how much area of triangle if each side of triangle is double

Answer 1

Taking an example of right angled triangle
let the height of triangle be X
and the Base of triangle be Y
area of triangle = 1/2 × Base × height
area of triangle = (X × Y)/2 ......(1)
if the sides are doubled
the height of new triangle = 2X
Base of new triangle = 2Y
area of new triangle = 1/2 × 2X × 2Y
area of new triangle = 2[ (X × Y)/2 ]
area of new triangle = 2 (area of triangle)
the area of triangle will be doubled