Given: klmn is a trapezoid, kl = mn ln = 89 , lh - altitude lm = 3, kn = 13. find: m∠lkn

m∠LNK = 86.8°

Step-by-step explanation:

∵ LH ⊥ KN at H

∵ LK = MN

∵ LM = 3

∴ HN = (13 - 3) ÷ 2 + 3 = 8 ⇒ isosceles trapezium

∵ LN = 89

∴ LH = √(89² - 8²) = 88.64

∵ KH = (13 - 3) ÷ 2 = 5 ⇒ isosceles trapezium

∵ tan ∠LKN = LH/KH = 88.64/5

∴ m∠LKN = 86.77° ≅ 86.8°

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons