Question

All the dimensions of a triangle were multiplied by the same factor. If the base of the triangle went from 1 centimeter to 3 centimeters, the are of the triangle was multiplied by

Nine
Three
Twelve
Six

Answer 1

 the area of the triangle was multiplied by 9

Answer 2

the area is multiplied by 9.

let x be the base
let y be the height

since all dimensions were multiplied by the same number, 3,

original area,
1/2 × x × y = (1/2)xy

New area,
1/2 × 3x × 3y = (1/2)(9)xy

hence, area is multiplied 9 times.