If John can paint half of a room in two-thirds of an hour, what part of the room can he paint in a full hour?

Step-by-step explanation:

Step one:

given data

we can express the given data mathematically as

John can paint 0.5room in 2/3 hours

let the part of the room he can paint in an hour be x

so

if he takes 2/3 hours to paint 0.5 room

then he will take 1 hour to paint x

cross multiply we have

x= 0.5/2/3

x=0.5*3/2

x= 1.5/2

x=0.75 part of the room

75/100= 15/20=3/4 part

Part A:

13²-5²=c

169-25=144

√144=12

Your height is 12.

Part B:

Base:

20(10)=200

Two triangular faces:

5(13)=65

65(2)=130

Rectangular faces:

20(13)=260

260(2)=520

200+130+520=850

They would need 850 cm of cardboard.

Hope this helps! Have an amazing day!