A triangle has sides with lengths of 5, 9, and 8. What is the radius of the triangles inscribed circle?

Answer 1

#1.809#

Refer to the figure below

As the sides of the triangle are 5, 8 and 9:
#x+y=9#
#x+z=8#
#y+z=5# => #z=5-y#
#-> x+5-y=8# => #x-y=3#

Adding the first and last equations
#2x=12# => #x=6#

Using the Law of Cosines:
#5^2=9^2+8^2-2*9*8*cos alpha#

#cos alpha=(81+64-25)/144=120/144=5/6#

#alpha=33.557^@#

In the right triangle with #x# as cathetus, we can see that
#tan (alpha/2)=r/x#

#r=6*tan (33.557^@/2)# => #r=1.809#

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Answer 2

Radius of inscribed circle is #=6/sqrt(11) ~= 1.81#

The radius of a circle inscribed in a triangle is #color(white)("XXX")r= ("Area"_triangle)/s# where #s# is the semi-perimeter of the triangle.
For a triangle with sides #5, 9, and 8# #color(white)("XXX")s=11#
Using Heron's formula #color(white)("XXX")"Area"_triangle = sqrt(s(s-a)(s-b)(s-c))#
#color(white)("XXXXXXX")=sqrt(11(6)(2)(3)) = 6sqrt(11)#
And the required radius is #color(white)("XXX")(6sqrt(11))/11 = 6/sqrt(11)#
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Answer 3

The radius (rr) of the inscribed circle in a triangle can be found using the formula:

r=Asr = \frac{A}{s}

where AA is the area of the triangle and ss is the semi-perimeter of the triangle, given by:

s=a+b+c2s = \frac{a + b + c}{2}

where aa, bb, and cc are the lengths of the sides of the triangle.

To find the area of the triangle, we can use Heron's formula:

A=s(sa)(sb)(sc)A = \sqrt{s(s - a)(s - b)(s - c)}

Given that the lengths of the sides of the triangle are a=5a = 5, b=9b = 9, and c=8c = 8, we can calculate ss and AA:

s=5+9+82=11s = \frac{5 + 9 + 8}{2} = 11

A=11(115)(119)(118)A = \sqrt{11(11 - 5)(11 - 9)(11 - 8)} =11(6)(2)(3)= \sqrt{11(6)(2)(3)} =396= \sqrt{396}

Now, we can find the radius rr:

r=39611r = \frac{\sqrt{396}}{11}

r19.911r \approx \frac{19.9}{11}

r1.81r \approx 1.81

So, the radius of the inscribed circle in the triangle is approximately 1.811.81.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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