Mathematics Applications & Interpretation (AI) International Baccalaureate (IB) Practice Question: The Bermuda Triangle is a region of the Atlantic Ocean with Miami (M), Bermuda (B), and San Juan (S) as vertices, as sho...

• Substitute side lengths into the cosine rule M1
• Correct substitution: $\cos \theta=\frac{1660^2+1550^2-1670^2}{2(1660)(1550)}$ A1
• $\theta = 62.6^\circ$ ($62.5873 \ldots^\circ$) A1

3 marks total

NoteAccept $1.09$ rad ($1.09235 \ldots$).

• Substitute correct values into the area of a triangle formula M1
• Correct substitution: $A=\frac{1}{2}(1660)(1550) \sin (62.5873 \ldots^\circ)$ A1
• $A = 1\,140\,000$ ($1.14 \times 10^6$, $1\,142\,043 \ldots$) $\text{km}^2$ A1

3 marks total

NoteAccept $1\,150\,000$ ($1.15 \times 10^6$, $1\,146\,279 \ldots$) $\text{km}^2$ from use of $63^\circ$. Other angles and their corresponding sides may be used.