Example 5: Fill in the given values to find the surface area: SA = π·r·s + π·r2 SA = π·8·24 + π·82 SA = 804.2 cm2   rounded to 1 d.p. Example 6: Find the Surface Area: The difficulty with this example is determining the values we need. Clearly we're missing the slant heght s. On the right is a right triangle showing the height and radius of the cone. We can use the Pythagorean Theorem to find s:       s2 = 152 + 202       s2 = 625       s = 25       Now we can find the surface area:          SA = π·r·s + π·r2          SA = π·15·25 + π·152          SA = 1885.0 cm2   rounded to 1 d.p. Example 7: The surface area is 1250 cm2. Find the slant height s. SA = π·r·s + π·r2 1250 = π·5·s + π·52 1250 = 15.71s + 78.54 1171.46 = 15.71s 74.6 cm = s   rounded to 1 d.p. Finally, let's look at some mixed problems ... Intro | Volume of a Cone | Surface Area of a Cone | Mixed Problems Resources Content, HTML, graphics & design by Bill Willis 2024