The perimeter of △cde is 55 cm. a rhombus dmfn is inscribed in this triangle so that vertices m, f, and n lie on the sides cd, ce, and de respectively. find cd and de if cf=8 cm and ef=12 cm.

CD=14

DE=21

Step-by-step explanation:

ΔCDE is similar to ΔFNE (∠E≅∠E, ∠NFE≅∠DCE) by AA similarity

Using Thales' Intercept Theorem Corollary, you know that:

EN/ED=EF/EC=NF/CD=12/20

Let DN be 8x and NE be 12x

Let NF be 12y and CD be 20y

Then you have a system of equations:

20x+20y+20=55

8x=12y

By solving them, you get y=0.7 and x=1.05⇒

DE=21 and CD=14

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116