1.39: Figure 1 shows a right prism Triangle is a cross section of the prism.

4PM1/1/November/2024 — Question 4 · 6 marks

1.39 diagram 1
Figure 1 shows a right prism ABCDEF\displaystyle ABCDEF
Triangle CDE\displaystyle CDE is a cross section of the prism.
• ∠DCE=∠ABF=90∘\displaystyle \angle DCE = \angle ABF = 90^\circ
• ∠EDC=∠FAB=40∘\displaystyle \angle EDC = \angle FAB = 40^\circ
• DE=AF=15\displaystyle DE = AF = 15 cm
• EF=DA=CB=20\displaystyle EF = DA = CB = 20 cm
Find, in degrees to one decimal place, the size of the angle between the line FD\displaystyle FD and the plane DCBA\displaystyle DCBA
(6)