The area of the new triangle will be 90cm
Given that the area of a triangle is expressed as:
If the base and height are scaled by a factor of 5, then the area will be:
5(bh) = 5(18)
5(bh) = 90cm²
Hence the area of the new triangle will be 90cm²
Learn more on area of triangle here: https://brainly.com/question/17335144