The formula for the area of a trapezium is as follows:
<span>area=<span>12</span>(a+b)h
</span>
Let a be the shorter base. Then a = h + 3.
Let b be the longer base. Then b = h + 7.
Substituting these values for a and b in the general formula gives:
<span>
area = 225 = <span>12</span>(h+3+h+7)h = <span>h^2</span>+5h</span>
So you need to solve the following quadratic:
<span><span>h^2</span>+5h−225=0</span>
Step 1: Use quadratic formula with a=1, b=5, c=-225.
<span>h=<span><span><span>−b</span>±<span>√<span><span>b2</span>−<span><span>4a</span>c</span></span></span></span><span>2a</span></span></span><span>h=<span><span><span>−<span>(5)</span></span>±<span>√<span><span><span>(5)</span>2</span>−<span><span>4<span>(1)</span></span><span>(<span>−225</span>)</span></span></span></span></span><span>2<span>(1)</span></span></span></span><span>h=<span><span><span>−5</span>±<span>√925</span></span>2</span></span><span><span>h=<span><span><span>−5/</span>2</span>+<span><span><span><span>5/2</span><span>√37</span></span><span> or </span></span>h</span></span></span>=<span><span><span>−5/</span>2</span>+<span><span><span>−5/</span>2</span><span>√37
</span></span></span></span>Answer:<span><span>h=<span><span><span>−5/</span>2</span>+<span><span><span><span>52</span><span>√37</span></span><span> or </span></span>h</span></span></span>=<span><span><span>−5/</span>2</span>+<span><span><span>−5/</span>2</span><span>√<span>37</span></span></span></span></span>
Answer:
50°
Step-by-step explanation:
As usual, the diagram is not drawn to scale.
The chord divides the circle into two arcs that have a sum of 360°. If we let "a" represent the measure of the smaller arc, then we have ...
a + (a+160°) = 360°
2a = 200° . . . . . . . . . . . subtract 160°
a = 100°
The measure of the angle at A is 1/2 the measure of the subtended arc:
acute ∠A = a/2 = (1/2)·100° = 50°
_____
<em>Comment on this geometry</em>
Consider a different inscribed angle, one with vertex V on the circle and subtending the same short arc subtended by chord AB. Then you know that the angle at V is half the measure of arc AB. This is still true as point V approaches (and becomes) point A on the circle. When V becomes A, segment VA becomes tangent line <em>l</em>, and you have the geometry shown here.
Answer:
............................
Even though it has not happened yet again
