Achord in a circle is 18 cm long and is 5 cm from the center of the circle. how long is the radius of the circle?

The length of the radius is 10.30 cm

Step-by-step explanation:

∵ The length of the chord = 18 cm

∵ The ⊥ distance from the center to it = 5 cm

∴ ⊥ distance bisects chord (18/2 = 9)

By using Pythagoras Theorem (⊥ distance , half chord , radius)

∴ r² = 9² + 5² = 81 + 25 = 106

∴ r = √106 = 10.30 cm

you need to add a picture

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

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