user: I need to calculate the area of three different triangles for a construction project I'm working on: one with a base of 15 meters and a height of 20 meters, another with a base of 25 meters and a height of 30 meters, and a third with dimensions of 35 meters by 40 meters for the base and height, respectively. Can you give me the areas for each triangle?

Available functions:
name: calculate_triangle_area
description: Calculates the area of a triangle given its base and height.
parameters: type: dict
properties: base: type: integer
description: The base of the triangle, in meters.
height: type: integer
description: The height of the triangle, in meters.
required: base
height