Because this shape has 2 right angles, we can confirm that it has one set of parallel sides and is a trapezoid. Therefore, use the formula for area of a trapezoid, .5(b1+b2)(h)
.5(1+6)(12)
.5(7)(12)
42 units^2
BO is double that of DO. In other words, BO is two times longer than DO. The answer is choice B
For example, if DO were 3 units long, then BO would be 6 units long (2*3 = 6). This works because the triangles DCO and BAO are similar triangles. The corresponding sides are in the same ratio or proportion to one another. The larger triangle (BAO) has sides that are twice as long as the smaller triangle's (DCO) corresponding sides.
Side note: we can prove the triangles to be similar using the AA (angle angle) similarity theorem. The first pair of angles are the vertical angles DOC and BOA which are congruent to each other.The second pair is CDB and ABD which are congruent by the alternate interior angle theorem. Check out the attached image for a visual.
First combine like terms ( x's go with x's), so subtract 2x to both sides and you get:
5+ (3x-2x) = 6 + (2x-2x)
5 + x = 6
Isolate x by bringing 5 to the other side by subtraction
(5-5) + x = (6-5)
x = 1
Hope this helped!
Solution :
Given that :
The radius of circle A = 6 cm
The radius of circle C = 4 cm
In circle A
The length of arc EF =
= 14.653 cm
In circle C
The length of arc GH =
= 9.769 cm
Therefore,
The length of EF is 14.653 cm
The length of GH is 9.769 cm
The length of EF is 1.5 times the length of GH
i.e. 14.653 = 1.5 x 9.769
14.653 = 14.653
Hence proved.