Answer:
BC 4 in
Step-by-step explanation:
The steps for construction;
- Using a ruler draw line AB 4 inches and label the end points A and B
- At point A , using a protractor, measure angle 60° and mark with point. Draw a line from A passing through this point extending to a length of 4 inches
- Mark that point C.
- Using the ruler, join point C and B and measure BC.
From calculation, length BC can be found by the formula;
------where a=b=4 in , cos A = cos 60°
BC = 4 in