какую массу сульфата калия и воды надо взять для приготовления 300 г 20% раствора?

Из точки, отстоящей на плоскости на расстоянии 10 см, проведены 2 наклонные под углом 45° к плоскости, а их проекции составляют между собой угол 120°.
найти расстояние между концами наклонных.

                            ПЕРЕВЕДИТЕ НА РУССКИЙ 

"What  a pity" Michael said "they aren't chocolate "

"Well , they are,sometimes" said Mrs. Corry ,"I often eat them,if i can't sleep at night.I think ,my dear" -she turned to Mary Poppins "I think you want some gingerbrade.Now,my darling" said Mrs.Corry an a soft voice and smiled sweetly at Jane and Michael ,"won't you come and take some ?It's very special today.How many ?"

     "Four each" said Mary Poppins ."That's twelve.One dozen."

 "I'll make it a baker's dozen-take thirteen" said Mrs. Corry.

  So Jane and Michael chose thirteen bars of gingerbread,each with a golden paper star.Michael tried one of them.

 "Good?" asked Mrs.Corry , and then she cried in her thin voice : "Hooray,hooray!".Then she stopped and her face grew serious.

   "But remember-you must pay"

    Mary Poppins opened her bag and took out three coins.She gave them to Jane and Michael.

  "Now " said Mrs.Corry ."Stick the coins on my coat! They won't come off!"

     Mary Poppins was the first to stick her coin on the Mrs. Corry's coat.And stuck.Then Jane and Michael put theirs on-Jane's on the right shoulder and Michael's on the left one.

   "How strange" said Jane

"I'm afraid we must be off now ,Mrs.Corry " said Mary Poppins .

"Well,my dear Mis Poppins , it has been a very pleasant visit.And you'll come again soon,won't you,with Jane and Michael and the twins ?"

    They Nodded.Then Mrs,Corry Came closer to the children with a curious look on her face.