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2 years ago

Work out the value of A

Mathematics

1 answer:

Mkey [24]2 years ago

6 0

Answer:

that is really so difficult ? what do you not understand here ? please let me know, if you need any further explanations.

you know what the perimeter is ? if it's the circumference, the way around the object. in other words, the distance you have to walk, when going along all sidelines of the object.

so the perimeter is the sum of of all side lengths.

56 = x - 1 + 3x + 3x + 1 = 7x

x = 8

that gives us the side lengths :

x - 1 = 7 cm

3x = 21 cm

3x + 1 = 22 cm

the formula for the area of a triangle

A = baseline × height / 2

the advantage of a right-angled triangle in this regard is that the sides enclosing the 90 degree angle are already "acting" as baseline and the height (standing on the baseline with a 90 degree angle).

so, we can simply say here, the 3x side is the baseline, and the x-1 side is also the height.

therefore,

A = 21×7/2 = 147/2 = 73.5 cm²

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2 years ago

Write the expression as either the sine, cosine, or tangent of a single angle. (2 points)

sattari [20]

Answer:

cos(π/3)cos(π/5) + sin(π/3)sin(π/5) = cos(2π/15)

Step-by-step explanation:

We will make use of trig identities to solve this. Here are some common trig identities.

Cos (A + B) = cosAcosB – sinAsinB

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Given cos(π/3)cos(π/5) + sin(π/3)sin(π/5) if we let A = π/3 and B = π/5, it reduces to

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cosAcosB + sinAsinB = cos(A – B). Therefore,

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2 years ago

I don’t understand what this question is asking for

Elden [556K]

Answer:

(d) m∠AEB = m∠ADB

Step-by-step explanation:

The question is asking you to compare the measures of two inscribed angles. Each of the inscribed angles intercepts the circle at points A and B, which are the endpoints of a diameter.

<h3>applicable relations</h3>

Several relations are involved here.

The measures of the arcs of a circle total 360°
A diameter cuts a circle into two congruent semicircles
The measure of an inscribed angle is half the measure of the arc it intercepts

<h3>application</h3>

In the attached diagram, we have shown inscribed angle ADB in blue. The semicircular arc it intercepts is also shown in blue. A semicircle is half a circle, so its arc measure is half of 360°. Arc AEB is 180°. That means inscribed angle ADB measures half of 180°, or 90°. (It is shown as a right angle on the diagram.)

If Brenda draws angle AEB, it would look like the angle shown in red on the diagram. It intercepts semicircular arc ADB, which has a measure of 180°. So, angle AEB will be half that, or 180°/2 = 90°.

The question is asking you to recognize that ∠ADB = 90° and ∠AEB = 90° have the same measure.

m∠AEB = m∠ADB

_____

<em>Additional comment</em>

Every angle inscribed in a semicircle is a right angle. The center of the semicircle is the midpoint of the hypotenuse of the right triangle. This fact turns out to be useful in many ways.

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1 year ago