22.
pythagorean theorem says legs a and b and hypotenuse c of a right triangle are related via the equation c²=a²+b². in other words, adding the sum of the squares of the legs get you the square of the hypotenuse
if the hypotenuse is 4 meters long, c = 4.
if one leg is 3 meters long, we can choose either a or b to be 3. it does not really matter. let us choose a = 3. now we have to find b.
if we have c²=a²+b², we can solve for b.
subtract a² both sides to get c²-a²=b², and then square root both sides to get
b = √(c²-a²)
plugging in our info we get
b = √(4²-3²) = √(16 -9) = √7
so the answer is √7 meters for 22
23
two triangles are similar, then the proportion of their sides are the same. the propotion between the smaller triangles' hypotenuse and 2cm leg is 5cm/3cm.
notice how the bigger triangle just have a doubled hypotenuse. therefore, the bigger triangle's x and y are just the corresponding smaller triangle values doubled.
x = 6 and y = 8
Changed both of them to a fraction

x = 1040/43 = $24.19 per day.
y = 10/43 = $0.23 per mile.
"Two significant figures" means that a digit after the second one could actually be anything ... it wasn't measured. 'X' could be anything from 230 to 239. 'Y' could be anything from 400 to 409.
The greatest possible value of that fraction is. (239)/(409 squared) .
13)
there are 2π radians in 1 revolution, and there are 60 seconds in 1 minute, so keeping that in mind, then,

14)


15)
what is the radians per seconds "w" in revolutions per minute? just another conversion like in 13)