Answer:
17) h=I(1-cosθ); 18) h=1.404.
Step-by-step explanation:
17) h=I-BC;
In ΔABC: m(∠C)=90°, m(∠B)=θ, AB=I, then BC=AB*cos(∠B); ⇒ BC=Icosθ;
Then h=I-Icosθ or h=I(1-cosθ).
18) if I=6 and θ=40°, then h=6(1-cos40°)≈6*(1-0.766)=1.404, where cos40°≈0.766.
For more details see the attachment.
