Answer:
1) The length of BE ≅ 7.73
2) The beam clear the wires in its way to standing up straight because the length of the wire less than the height of the wires by 0.332
Step-by-step explanation:
Figure 1:
∵ The equilateral Δ share the side of the square
∵ The length of the side of the square = 4
∴ The length of the side of the Δ = 4
In Δ EAB:
∵ AE = 4 and AB = 4
∵ m∠A = 90 + 60 = 150°
By using cos Rule:
∵ (BE)² = (AE)² + (AB)² - 2(AE)(AB)cosA
∴ (BE)² = (4)² + (4)² - 2(4)(4)cos150 = 59.71281
∴ BE = 7.7274 ≅ 7.73
Figure 2:
∵ The beam makes ∠40° with the ground
∵ The top of the beam is above ground by 8 ft
∴ The length of the beam = 8/sin(40) = 12.446
∵ The beam makes ∠60° with the ground
∵ The length of the beam = 12.44579
∴ The height of the top of the beam from the ground
= 12.44579 × sin(60) = 10.77837
∵ The height between the top of the beam and the wires in this
position is 2
∴ The height of the wires from the ground = 10.778 + 2 = 12.778
∵ The length of the beam = 12.446
∴ 12.446 < 12.778
∴ The beam clear the wires in its way to standing up straight
