I note in my accounts book positive numbers for profits and negative numbers for losses that I make in my business. These are the entries in the book for the last seven days: 21, –19, 11, –20, 17, 25 and –13. How much profit did I make in the last week?
In the given figure (not drawn to scale), OABC is a quadrilateral with ABC on horizontal ground and O is vertically above A. M is the mid-point of BC. If ∠BAC = 90°, AB = AC = 16 cm and OA = 12 cm, calculate the length of OB.
I don't understand what we are finding. OC or OB clearly angle OAB is 180 degrees,