Things would be a lot clearer if you wrote
CN^2 = 13^2 + 18^2 - 2*13*18 cos 45
= 169 + 324 - 468*√2/2
= 162.07
CN = 12.73
Why would you use square roots in the following question:
Chang is participating in a charity bicycle road race. The route starts at Centreville and travels east for 13 km to Eastdale. He then makes a 135° turn and heads northwest for another 18 km, arriving at Northcote. The final leg of the race returns to Centreville.
a) What is the total length of the race, to the nearest tenth of a kilometre? (2 marks)
Here is my work for the question:
CN2=132+182-2-13-18-cos 45
CN2= 169+324-234√2
CN= 12.7308 km.
The total distance of the race would be 13+18+12.7=43.7 km.
1 answer
1 answer