two similar triangles have areas of 5cm square and 20 cm square respectively. if base of the smaller triangle is 4cm, find the base of the larger triangle.

Question

IGCSE mathematics. geometry

Answer 1

The area of the larger triangle is equal to the area of the smaller one times the square of the scale factor:

 

Area of larger triangle = Area of smaller triangle * (scale factor)²

 

Hence:

 

(Area of larger triangle)/(Area of smaller triangle) = (scale factor)²

 

20/5 = (scale factor)²

 

4 = (scale factor)²

 

√4 = √(scale factor)²

 

2 = scale factor

 

Length of Base of larger triangle = Length of base of smaller triangle * scale factor

 

Can you finish it from here?