Here are the solutions to the geometry problems.
: Top diagram
a) Calculate the length of AB
Step 1: Calculate the lengths of AD and CD using △ADC.
In △ADC, ∠ADC=90∘, ∠ACD=67∘, and AC=6.
We use trigonometric ratios:
AD=ACsin(∠ACD)
AD=6sin(67∘)
AD≈6×0.9205
AD≈5.523units
CD=ACcos(∠ACD)