If there is direct variation and y = 27 when x = 4, find y when x =12. A. 9
B. 81
C. 1.78
D. 0.56

B

Step-by-step explanation:

Given y and x vary directly then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = 27 when x = 4 , then

27 = 4k ( divide both sides by 4 )

= 6.75 = k

y = 6.75x ← equation of variation

When x = 12 , then

y = 6.75 × 12 = 81

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5