If the difference of circumference and diameter of circle is 90 cm find the diameter and area of circle HELP

a) 42.056 cm   b) 1,388.435 cm^2

Step-by-step explanation:

a)

Circumference (c)  = Diameter (d) x pi

In this case, d = c - 90.

You can plug in (d pi) for the c:    d = d pi - 90

Subtract the d and 90 from both sides:    90 = d pi - d

Factor out the d:   90 = (pi - 1) d

(Pi - 1) is approximately 2.14:    90 = 2.14 d

Divide both sides by 2.14:   90/2.14 = d

d (approximately) = 42.056 cm

b)

Area of a circle (A) = Radius squared (r^2) x pi

Radius is half the diameter. The diameter is 42.056, therefore the radius is 21.028.

A = pi (21.028 cm) ^2

A = 3.14 (442.176 cm^2)

A (approximately) = 1,388.435 cm^2

positive

step-by-step explanation:

the quadrant is facing upwards

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!