Question

Communities A,B and C are faced with acute water problem. The distance between communities A and B is 5km and that of A and C 7km. The angle between path AB and AC is 45degrees. If a well is dug for the three communities such that it would have equal distance to the path linking each communities. (a) Indicate by a way of sketching the exact place to dig the well? (b) Measure the distance between communities B and C?

Answer 1

a) by finding the incentre

b) 5 km

Explanation:

Let the communities A, B and C be shown by the three points of the triangle as shown in the figure below. As the angle between the path Ab and Ac is 45 degrees this is an isosceles triangle having two angles equal. As this is an isosceles triangle it must also have two sides equal .

a) the in center point can be used to have equal distance to the path linking each communities.

We take a compass and draw arcs on the two sides of the vertex and placing the compass on the arcs bisect each angle made by the triangles arms.

Joining the bisectors the lines meet at a point which is highlighted by a circle in the diagram.

This is the incentre which is equidistant from each vertex.

b) Using Pythagorus theorem

c² = a² + b²

7²= 5² + b²

b²= 24

b= 4.89= 5 km

The path between B and C is also 5 km.