Answer:
Yes, the angle formed between the ground and the ladder is safe
6.84 ft (nearest hundredth)
Step-by-step explanation:
We can use the cos trig ratio to determine the angle made between the 20ft ladder and 3ft from the base of the house (see first attached image for sketch).
[tex]\sf \cos(\theta)=\dfrac{A}{H}[/tex]
where:
- [tex]\theta[/tex] is the angle
- A is the side adjacent to the angle
- H is the hypotenuse
Given:
[tex]\sf \implies \cos(\theta)=\dfrac{3}{20}[/tex]
[tex]\sf \implies \theta=\cos^{-1}\left(\dfrac{3}{20}\right)[/tex]
[tex]\sf \implies \theta=81.37307344..^{\circ}[/tex]
Therefore, as the ladder is forming an 81.37° angle and 81.37...° > 70° the angle formed between the ground and the ladder is safe.
To find the furthest possible distance the ladder can be placed, set [tex]\theta[/tex] to 70° (max safe angle) and the hypotenuse (ladder length) to 20, then solve for A (see second attache image for sketch):
[tex]\sf \implies \cos(70^{\circ})=\dfrac{A}{20}[/tex]
[tex]\sf \implies A=20\cos(70^{\circ})[/tex]
[tex]\sf \implies A=6.840402867...\: \sf ft[/tex]
So the furthest possible distance the ladder can be placed to maintain a safe angle is 6.84 ft (nearest hundredth).
