Find longest side of right-angled triangle
Use cos to calculate hypotenuse of right-angled triangle, using Casio calculator.
0:00 Introduction
0:16 Trigonometry
0:25 SOHCAHTOA
0:40 Label sides: hypotenuse, adjacent, opposite
1:22 Formula using cosine ratio = adjacent / hypotenuse
1:50 Rearrange formula
2:05 Use Casio calculator
2:35 Round answer to 3 sf
2:55 Use FIX on Casio calculator to round to 1dp
3:26 Check answer is sensible
3:50 Common error