1. The major arc ED has measure 180 degrees since ED is a diameter of the circle. The measure of arc EF is $(2x+10)^\circ$ , so the measure of arc DF is

$m\widehat{DF}=360^\circ-180^\circ-(2x+10)^\circ=(170-2x)^\circ$

The inscribed angle theorem tells us that the central angle subtended by arc DF, $\angle DOF$ , has a measure of twice the measure of the inscribed angle DEF (which is the same angle OEF) so

$m\angle DOF=2m\angle OEF=64^\circ$

so the measure of arc DF is also 64 degrees. So we have

$170-2x=64\implies106=2x\implies\boxed{x=53}$

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2. Arc FE and angle EOF have the same measure, 56 degrees. By the inscribed angle theorem,

$m\angle EOF=2m\angle EDF\implies56^\circ=2m\angle EDF\implies m\angle EDF=28^\circ$

Triangle DEF is isosceles because FD and ED have the same length, so angles EFD and DEF are congruent. Also, the sum of the interior angles of any triangle is 180 degrees. It follows that

$m\angle EFD+m\angle EDF+m\angle DEF=180^\circ\implies\boxed{m\angle EFD=76^\circ}$

Triangle OFE is also isosceles, so angles EFO and FEO are congruent. So we have

$m\angle EFO+m\angle FEO+m\angle EOF=180^\circ\implies\boxed{m\angle EFO=62^\circ}$

7 0

3 years ago

How do I solve this equation: (3+2i)+(2+bi)=5-4i

oksian1 [2.3K]

$(3+2i)+(2+bi)=5-4i$

6 0

3 years ago

Alvin is 14 years older than elga's The sum of their ages is 94 what is elga'ss age

Sonja [21]

Elga’s age is 40 and Alvin’s age is 54

8 0

3 years ago

Read 2 more answers

NEED HELP ASAP PLEASE WITH #9 and #10!!

ICE Princess25 [194]

9) Because the total number of pencils is 180 and you will use them up in 30 days, the equation will have to equal 0 total pencils when 30 is substituted in for the time factor, or x. This already takes our choice 3 because it doesn’t meet this criteria.
The answer to how many pencils in 20 days could be answered by plugging in 20 for x. Choice 4 cannot work because it results in a negative number of pencils. Choices 1 and 2 use the same equation, so by plugging in 20 it is clear choice 2 is the correct answer.

10) A line parallel to the go en equation would have the same slope, -3, which means choices 1 and 4 are out. Plug in (-2,5) into both choices 2 and 3. Plugging -2 into x in choice 2 gives -5, and in choice 3 gives 5 for the y value. Therefore choice 3 is correct.

8 0

3 years ago