Answer:-8
Step-by-step explanation:
Answer:
A) 220.5 mm^2
Step-by-step explanation:
<u>Explanation</u>:-
Given A regular triangular pyramid has a base of area is 31.5mm^2
and also given surface area of triangular pyramid is 252 mm ^2
by using formula
surface area of regular triangular pyramid = base of area + half of lateral surface.

252 = 31.5 + 

220.5 = lateral area of triangular pyramid
lateral area of triangular pyramid = 220.5 mm^2
Answer:

Step-by-step explanation:
Before we find x, we need to set up this triangle a little more. We need to find the triangle's altitude before we can solve for x. We will use the heartbeat method to find the altitude.
Let altitude = y; solve for y:




Now that we know the altitude, we can use the Pythagorean Theorem to find the hypotenuse (x).





Since c and x are the same; c is just the hypotenuse in the Pythagorean Theorem.

Slope formula: y2-y1/x2-x1
= 12-5/3-2
= 7/1
= 7
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