From the top of a tower, the angle of depression to the bottom of a pillar on the same surface of height 20m is 60° If the a angle of depsession from the top of the . pillar to the bottom of the lower is 22. find the height of the tower. ( Ton 220 - 0,4)

Let AB=height of the building=100m

DE=AC=AB+BC=h= height of the tower

∠ADC=60

∘∠BDC=60 ∘

Now

tan30 ∘ = CDCB

= dx

31 = dx

(1)tan60 ∘ = CDCA

= dx+100

3 = dx+100

(2)From (1)d= 3

x (3)Substituting (3) in (2)

3 = 3 x(x+100)

3x=x+100

2x=100

x=50

Height of the tower=DE=h=AB+CB=100m+x=100m+50m=150m

refer to the attachment...

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the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.